View source for Unit 731

{{Short description|Japanese biological and chemical warfare unit (1936–1945)}}
{{Use dmy dates|date=February 2024}}
{{Infobox civilian attack
| image = Unit_731_-_Complex.jpg
| image_upright = 1.1
| caption = The Unit 731 complex
| title = Unit 731
| location = [[Pingfang]], [[Harbin]], [[Heilongjiang]], [[Manchukuo]] (now part of [[China]])
| coordinates = {{Coord|45|36|31|N|126|37|55|E|region:CN-HL_type:landmark|display=inline}}
| date = 1936–1945
| type = {{ubl|[[Unethical human experimentation|Human experimentation]]|[[Biological warfare]]|[[Chemical warfare]]}}
| fatalities = Estimated 200,000<ref name="Kristof">{{cite news |last=Kristof |first=Nicholas D.B. |date=1996-03-17 |title=Unmasking Horror – A Special Report. Japan Confronting Gruesome War Atrocity |url=https://www.nytimes.com/1995/03/17/world/unmasking-horror-a-special-report-japan-confronting-gruesome-war-atrocity.html |newspaper=The New York Times |access-date=2019-07-14 |archive-date=2019-07-14 |archive-url=https://web.archive.org/web/20190714031133/https://www.nytimes.com/1995/03/17/world/unmasking-horror-a-special-report-japan-confronting-gruesome-war-atrocity.html |url-status=live }}</ref> to 300,000<ref>{{cite news |last=Watts |first=Jonathan |date=2002-08-28 |title=Japan guilty of germ warfare against thousands of Chinese |url=https://www.theguardian.com/world/2002/aug/28/artsandhumanities.japan |newspaper=The Guardian |access-date=2019-07-14 |archive-date=2019-08-06 |archive-url=https://web.archive.org/web/20190806103833/https://www.theguardian.com/world/2002/aug/28/artsandhumanities.japan |url-status=live }}</ref><br />
* 200,000 from biological warfare<ref name="Kristof"/><ref name="Liu">{{cite book |editor-last1=Liu |editor-first1=Huaqiu |date=2000 |title=军备控制与裁军手冊 |trans-title=Handbook on Arms Control and Disarmament |language=zh |publisher=National Defense Industry Press |page=368 |isbn=7-118-02282-9 |url=https://books.google.com/books?id=J1VQAAAACAAJ}}</ref>
* Over 3,000 from in-facility experiments (1940–1945, not including branches)<ref name="trialmaterials">{{cite book |publisher=[[Foreign Languages Publishing House (North Korea)|Foreign Languages Publishing House]] |year=1950 |title=Materials on the Trial of Former Servicemen of the Japanese Army Charged With Manufacturing and Employing Bacteriological Weapons |url=https://archive.org/details/MaterialsOnTheTrialOfFormerServicemen}}</ref>{{rp|20}}
* At least 10,000 prisoners killed<ref name="NYannals1">{{cite journal |last1=Harris |first1=Sheldon |date=December 1992 |title=Japanese Biological Warfare Research on Humans: A Case Study of Microbiology and Ethics |journal=Annals of the New York Academy of Sciences |volume=666 |issue=1 |pages=30–31 |doi=10.1111/j.1749-6632.1992.tb38021.x |pmid=1297279 |bibcode=1992NYASA.666...21H }}</ref>
* No documented survivors
| perps = {{ubl|[[Shirō Ishii]]|[[Masaji Kitano]]|[[Epidemic Prevention and Water Purification Department]]}}
| weapons = {{ubl|[[Biological weapon]]s|[[Chemical weapon]]s|[[Explosive]]s}}
}}

{{Nihongo|'''Unit 731'''|731部隊|Nana-san-ichi Butai|lead=yes}},{{NoteTag|The Japanese word ''[[:wikt:butai|butai]]'' is variously translated using military terms such as "unit", "detachment", "regiment", or "company".}} officially known as the '''Manchu Detachment 731''' and also referred to as the '''Kamo Detachment'''<ref name="trialmaterials" />{{rp|198}} and the '''Ishii Unit''',<ref name="ciadoc">{{Cite web |title=Human Experimentation at Unit 731 |url=https://www.pacificatrocities.org/human-experimentation.html |access-date=2024-05-28 |website=Pacific Atrocities Education}}</ref> was a secret research facility operated by the [[Imperial Japanese Army]] between 1936 and 1945. It was located in the [[Pingfang, Harbin|Pingfang]] district of [[Harbin]], in the [[Japanese puppet state]] of [[Manchukuo]] (now part of [[Northeast China]]), and maintained multiple branches across [[mainland China]] and [[Southeast Asia]].

Unit 731 was responsible for large-scale [[biological warfare|biological]] and [[chemical warfare]] research, as well as lethal [[unethical human experimentation|human experimentation]]. The facility was led by General [[Shirō Ishii]] and received strong support from the Japanese military. Its activities included infecting prisoners with deadly diseases, conducting [[vivisection]], performing [[organ harvesting]], testing [[hypobaric chamber]]s, amputating limbs, and exposing victims to chemical agents and explosives. Prisoners—often referred to as "logs" by the staff—were mainly [[Han Chinese|Chinese]] civilians, but also included [[Russians]], [[Koreans]], and others, including children and pregnant women. No documented survivors are known.

An estimated 14,000 people were killed inside the facility itself.<ref name="The day the earth died">{{cite news |url=https://www.theguardian.com/theobserver/2003/mar/02/features.magazine37 |title=The day the earth died |newspaper=The Observer |date=2 March 2003 |last1=Hill |first1=Amelia}}</ref> In addition, biological weapons developed by Unit 731 caused the deaths of at least 200,000 people in Chinese cities and villages, through deliberate contamination of water supplies, food, and agricultural land.<ref name="Kristof" />

After the war, twelve Unit 731 members were tried by the [[Soviet Union]] in the 1949 [[Khabarovsk war crimes trials]] and sentenced to prison. However, many key figures, including Ishii, were granted [[Immunity from prosecution (international law)|immunity]] by the [[United States]] in exchange for their research data. The [[Harry S. Truman administration]] concealed the unit's crimes and paid stipends to former personnel.<ref name="Gold 2003 p109">Hal Gold, ''Unit 731 Testimony'', 2003, p. 109.</ref><ref>{{Cite book |last=Guillemin |first=Jeanne |title=Hidden Atrocities: Japanese Germ Warfare and American Obstruction of Justice at the Tokyo Trial |date=2017 |publisher=Columbia University Press |isbn=978-0-231-18352-9}}</ref>

On 28 August 2002, the [[Tokyo District Court]] formally acknowledged that Japan had conducted biological warfare in China and held the state responsible for related deaths.<ref>{{Cite web |date=2002-08-28 |title=Ruling recognizes Unit 731 used germ warfare in China |url=https://www.japantimes.co.jp/news/2002/08/28/national/ruling-recognizes-unit-731-used-germ-warfare-in-china/ |access-date=2023-01-03 |website=The Japan Times}}</ref><ref>{{Cite web |date=2002-08-28 |title=Japan guilty of germ warfare against thousands of Chinese |url=https://www.theguardian.com/world/2002/aug/28/artsandhumanities.japan |access-date=2023-01-03 |website=The Guardian}}</ref> Although both the United States and Soviet Union acquired and studied the data, later evaluations found it offered little practical scientific value.<ref>{{Cite journal |last=Leitenberg |first=Milton |date=January 2001 |title=Biological Weapons in the Twentieth Century: A Review and Analysis |url=https://www.tandfonline.com/doi/full/10.1080/20014091096774 |journal=Critical Reviews in Microbiology |volume=27 |issue=4 |page=270 |doi=10.1080/20014091096774 |pmid=11791799|url-access=subscription }}</ref>

== Formations ==
[[File:Building on the site of the Harbin bioweapon facility of Unit 731 関東軍防疫給水部本部731部隊（石井部隊）日軍第731部隊旧址 PB121201.JPG|thumb|Building of the Unit&nbsp;731 bioweapon facility in [[Harbin]]]]
The [[Empire of Japan]] initiated its [[biological weapon]]s program during the 1930s, due to the prohibition of biological weapons in interstate conflicts by the [[Geneva Protocol]] of 1925. They reasoned that the ban verified its effectiveness as a weapon.<ref name="Kristof"/> Japan's occupation of [[Manchuria]] began in 1931, after the [[Japanese invasion of Manchuria]].<ref name="montana1">{{cite web|url=https://www.montana.edu/historybug/yersiniaessays/shama.html |title=Japan – Insects, Disease, and History {{pipe}} Montana State University |publisher=Montana.edu |date= |access-date=2022-06-01}}</ref> Japan decided to build Unit 731 in Manchuria because the occupation not only gave the Japanese an advantage of separating the research station from their island but also gave them access to as many Chinese individuals as they wanted for use as test subjects.<ref name="montana1"/> They viewed the Chinese as no-cost assets and hoped this ready supply of test subjects would give them a competitive advantage in biological warfare.<ref name="montana1"/> Most of the victims were Chinese, but many victims were also of different nationalities.<ref name="Kristof"/> These facilities contained more than just medical research and experimentation areas; they also included spaces for detaining victims, essentially functioning as a prison.<ref name="Indiana University Press">{{cite book |last1=LaFleur| url=https://books.google.com/books?id=gGQYOvo9-AsC&q=Yoshimura+ |first1=William |last2=Böhme |first2=Gernot |last3=Shimazono |first3=Susumu |title=Dark medicine: rationalizing unethical medical research |date=2007 |publisher=Indiana University Press|pages=75–76|location=US| isbn=978-0-253-22041-7 }}</ref> The research and experimentation rooms were constructed around the detention area, allowing researchers to conduct their daily work while monitoring the prisoners.<ref name="Indiana University Press"/> 
Founded in 1936, Unit 731 expanded to include 3,000 staff members, 150 structures, and the capacity to detain up to 600 prisoners concurrently for experimental purposes.<ref name="United States Responses to Japanese">{{cite journal | pmc=4487829 | date=2014 | last1=Brody | first1=H. | last2=Leonard | first2=S. E. | last3=Nie | first3=J. B. | last4=Weindling | first4=P. | title=United States Responses to Japanese Wartime Inhuman Experimentation after World War II: National Security and Wartime Exigency | journal=Cambridge Quarterly of Healthcare Ethics | volume=23 | issue=2 | pages=220–230 | doi=10.1017/S0963180113000753 | pmid=24534743 }}</ref>

Unit 731 was operated as a clandestine division of Japanese [[Kwantung Army]], based in Manchuria during World War II. Led by Lieutenant General [[Shirō Ishii]], the organization dedicated to the advancement of biological weaponry within the imperial army was commonly referred to as the Ishii Network.<ref name="apjjf.org">{{cite web | url=https://apjjf.org/tsuneishi-keiichi/2194/article | title=Unit 731 and the Japanese Imperial Army's Biological Warfare Program | date=24 November 2005 }}</ref> The Ishii Network was headquartered at the Epidemic Prevention Research Laboratory, established in 1932 at the Japanese Army Military Medical School in [[Tokyo]]. Unit 731 was the first among several covert units established as offshoots of the research lab, serving as field stations and experimental sites for advancing biological warfare techniques. These efforts culminated in the experimental deployment of biological weapons on Chinese cities, a direct breach of the 1925 Geneva Protocol prohibiting the use of biological and chemical weapons in warfare. Participants in these activities were aware of the violations and recognized the inhumanity of using human subjects in laboratory experiments, prompting the establishment of Unit 731 and other secret units.<ref name="apjjf.org"/>

Under the direction of Shirō Ishii, the Epidemic Prevention Research Laboratory was established following his return from a two-year exploration of American and European research institutions. With the endorsement of high-ranking military officials, it was established for the purpose of developing biological weapons. Ishii aimed to create biological weapons with humans as their intended victims, and Unit 731 was formed specifically to pursue this objective.<ref name="apjjf.org"/> Ishii organized a secret research group, the "Tōgō Unit", for chemical and biological experimentation in Manchuria.<ref name="apjjf.org"/>

In 1936, Emperor [[Hirohito]] issued a decree authorizing the expansion of the unit and its integration into the Kwantung Army as the Epidemic Prevention Department.<ref>Daniel Barenblat, ''A plague upon humanity'', 2004, p. 37.</ref> It was divided at that time into the "Ishii Unit" and the "Wakamatsu Unit", with a base in [[Changchun|Xinjing]]. From August&nbsp;1940 on, the units were known collectively as the "Epidemic Prevention and Water Purification Department of the Kwantung Army" or "Unit&nbsp;731" for short.<ref>Yuki Tanaka, ''Hidden Horrors'', 1996, p. 136.</ref>

One of Ishii's main supporters inside the army was Colonel [[Chikahiko Koizumi]], who later served as [[Minister of Health, Labour, and Welfare|Japan's Health Minister]] from 1941 to 1945. Koizumi had joined a secret [[poison gas]] research committee in 1915, during [[World War I]], when he and other Imperial Japanese Army officers were impressed by the successful German use of [[chlorine gas]] at the [[Second Battle of Ypres]], in which the [[Allies of World War I|Allies]] suffered 6,000 deaths and 15,000 wounded as a result of the chemical attack.<ref name="Williams1989">{{Cite book |last1=Williams |first1=Peter |title=Unit 731: Japan's secret biological warfare in World War II |last2=Wallace |first2=David |date=1989 |publisher=Free Press |isbn=978-0-02-935301-1 |edition=1. American |location=New York}}</ref>{{rp|8–9}}<ref>{{Cite journal |last=Van der Kloot |first=William |date=2004 |title=April 1915: Five Future Nobel Prize-Winners Inaugurate Weapons of Mass Destruction and the Academic-Industrial-Military Complex |journal=Notes and Records of the Royal Society of London |volume=58 |issue=2 |page=152 |jstor=4142047 |issn=0035-9149}}</ref>

=== Zhongma Fortress ===
Unit Tōgō was set into motion in the [[Zhongma Fortress]], a prison and experimentation camp in Beiyinhe, a village {{convert|100|km|mi|sp=us}} south of [[Harbin]] on the [[South Manchuria Railway]]. The prisoners brought to Zhongma included common [[criminal]]s, captured bandits, and anti-Japanese partisans, as well as [[political prisoner]]s and people rounded up on false charges by the [[Kempeitai]]. Prisoners were generally well fed on a diet of [[rice]] or [[wheat]], [[meat]], [[Fish (food)|fish]], and occasionally even [[Alcoholic beverage|alcohol]], in order to be in normal health at the beginning of experiments. Then, over several days, prisoners were eventually drained of blood and deprived of nutrients and water. Their deteriorating health was recorded. Some were also [[vivisected]]. Others were deliberately infected with [[Plague (disease)|plague]] [[bacteria]] and other [[microbes]].{{citation needed<!--Previously "ibid". [[WP:IBID|Don't use that]]-->|date=June 2025}} A prison break in the autumn of 1934, which jeopardized the facility's secrecy, and an explosion in 1935, that was believed to be sabotage, led Ishii to shut down the Zhongma Fortress. He then received authorization to move to Pingfang, approximately {{convert|24|km|mi|sp=us}} south of Harbin, to set up a new, much larger facility.<ref>{{Cite book |last=Harris |first=Sheldon H. |url=https://archive.org/details/factoriesofdeath0000harr/page/29 |title=Factories of death: Japanese biological warfare 1932 - 45 and the American cover-up |date=1999 |publisher=Routledge |isbn=978-0-415-13206-0 |edition=Reprint |location=London |page=29}}</ref>

[[File:A close up photo of the Unit 731 square building taken by the aviation and photography class of Unit 731 in 1940.jpg|thumb|Close-up photo of the Unit 731 main "square building" taken by Unit 731's aviation and photography class in 1940]]

=== Other units ===
{{Main|Epidemic Prevention and Water Purification Department}}
In addition to the establishment of Unit&nbsp;731, the decree also called for the creation of an additional biological warfare development unit, called the Kwantung Army Military Horse Epidemic Prevention Workshop (later referred to as Manchuria [[Unit 100]]), and a chemical warfare development unit called the Kwantung Army Technical Testing Department (later referred to as Manchuria [[Unit 516]]). After the [[Second Sino-Japanese War|Japanese invasion of China]] in 1937, sister chemical and biological warfare units were founded in major Chinese cities and were referred to as Epidemic Prevention and Water Supply Units. Detachments included [[Unit 1855]] in [[Beijing]], [[Unit Ei 1644]] in [[Nanjing]], [[Unit 8604]] in [[Guangzhou]], and later, [[Unit 9420]] in [[Singapore]], [[British Malaya|Malaya]] (present-day [[Malaysia]]), [[Dutch East Indies|Indonesia]], the [[History of the Philippines (1898–1946)|Philippines]], [[Papua New Guinea]], [[Thailand]], and [[British rule in Burma|Burma]]. All of these units comprised Ishii's network, which, at its height in 1939, oversaw over 10,000 personnel.<ref>{{cite web|url=http://apjjf.org/-Tsuneishi-Keiichi/2194/article.html|title=Unit 731 and the Japanese Imperial Army's Biological Warfare Program – The Asia-Pacific Journal: Japan Focus|website=apjjf.org|date=24 November 2005 |access-date=2017-10-27|archive-date=2018-01-04|archive-url=https://web.archive.org/web/20180104190943/http://apjjf.org/-Tsuneishi-Keiichi/2194/article.html|url-status=live}}</ref> Medical doctors and professors from Japan were enticed to join Unit&nbsp;731 both by the rare opportunity to conduct human experimentation and the Army's strong financial backing.<ref name="NHK">The Truth of Unit 731: Elite medical students and human experiments (2017). NHK Documentary</ref>

== Experiments ==
{{Shōwa Statism|Atrocities}}
The military police and the Special Services Agency were responsible for finding victims to be test subjects for the unit, while a group of physicians were responsible for maintaining healthy victims and dispatching them for experimentations.<ref name="Indiana University Press"/> Not all individuals sent to Unit 731 underwent experiments; these experiments were reserved for healthy individuals, and once accepted into the program, the preservation of their health became a top priority.<ref name="Indiana University Press"/>

Human experiments involved intentionally infecting captives, especially Chinese prisoners of war and civilians, with disease-causing agents and exposing them to bombs designed to disperse infectious substances upon contact with the skin. There are no records indicating any survivors from these experiments; those who did not die from infection were murdered for autopsy analysis.<ref name="United States Responses to Japanese"/> After human experimentations, researchers commonly used either [[potassium cyanide]] or [[chloroform]] to kill survivors.<ref>{{cite book |last1=LaFleur| url=https://books.google.com/books?id=gGQYOvo9-AsC&q=Yoshimura+ |first1=William |last2=Böhme |first2=Gernot |last3=Shimazono |first3=Susumu |title=Dark medicine: rationalizing unethical medical research |date=2007 |publisher=Indiana University Press|page=75 |location=US| isbn=978-0-253-22041-7 }}</ref>

According to American historian [[Sheldon H. Harris]]:
<blockquote>The Togo Unit employed gruesome tactics to secure specimens of select body organs. If Ishii or one of his co-workers wished to do research on the human brain, then they would order the guards to find them a useful sample. A prisoner would be taken from his cell. Guards would hold him while another guard would smash the victim's head open with an ax. His brain would be extracted off to the pathologist, and then to the [[crematorium]] for the usual disposal.<ref>{{Cite book |last=Harris |first=Sheldon H. |url=https://archive.org/details/factoriesofdeath0000harr/page/28 |title=Factories of death: Japanese biological warfare 1932 - 45 and the American cover-up |date=1999 |publisher=Routledge |isbn=978-0-415-13206-0 |edition=Reprint |location=London |page=28}}</ref></blockquote>

Nakagawa Yonezo, [[professor emeritus]] at [[Osaka University]], studied at [[Kyoto University]] during the war. While he was there, he watched footage of human experiments and executions from Unit&nbsp;731. He later testified about the playfulness of the experimenters:<ref>{{cite book|last1=Gold|first1=Hal|title=Japan's Infamous Unit 731: First-hand Accounts of Japan's Wartime Human Experimentation Program |year=2019|publisher=Tuttle Publishing|isbn=978-0-8048-5219-7|page=222|last2=Totani|first2=Yuma.}}</ref>

<blockquote>Some of the experiments had nothing to do with advancing the capability of [[Biological warfare|germ warfare]], or of medicine. There is such a thing as professional curiosity: 'What would happen if we did such and such?' What medical purpose was served by performing and studying beheadings? None at all. That was just playing around. Professional people, too, like to play.</blockquote>

Prisoners were injected with diseases, disguised as [[Vaccine|vaccinations]],<ref>{{cite news|url=http://www.medicalbag.com/despicable-doctors/pure-evil-wartime-japanese-doctor-had-no-regard-for-human-suffering/article/472462/|title=Pure Evil: Wartime Japanese Doctor Had No Regard for Human Suffering|date=2014-05-28|website=Medical Bag|access-date=2017-03-28|language=en|archive-date=2017-03-29|archive-url=https://web.archive.org/web/20170329140410/http://www.medicalbag.com/despicable-doctors/pure-evil-wartime-japanese-doctor-had-no-regard-for-human-suffering/article/472462/|url-status=live}}</ref> to study their effects. To study the effects of untreated [[venereal disease]]s, male and female prisoners were deliberately infected with [[syphilis]] and [[gonorrhea]], then studied.<ref>{{cite journal | url=https://www.actasdermo.org/en-syphilis-human-experimentation-from-first-articulo-S1578219014002030 | doi=10.1016/j.adengl.2013.09.009 | title=Syphilis and Human Experimentation from the First Appearance of the Disease to World War II: A Historical Perspective and Reflections on Ethics | date=2014 | last1=Cuerda-Galindo | first1=E. | last2=Sierra-Valentí | first2=X. | last3=González-López | first3=E. | last4=López-Muñoz | first4=F. | journal=Actas Dermo-Sifiliográficas (English Edition) | volume=105 | issue=8 | pages=762–767 | doi-access=free | hdl=10486/713606 | hdl-access=free }}</ref> A special project, codenamed ''Maruta'', used human beings for experiments. Test subjects were gathered from the surrounding population and sometimes euphemistically referred to as {{nihongo|"logs"|丸太|maruta}}, used in such contexts as "How many logs fell?" This term originated as a joke on the part of the staff because the official [[Cover-up|cover story]] for the facility given to local authorities was that it was a [[lumber mill]]. According to a junior uniformed civilian employee of the Imperial Japanese Army working in Unit&nbsp;731, the project was internally called "Holzklotz", from the German word for log.<ref>{{cite book |last1=Cook |first1 = Haruko Taya |last2=Cook |first2 = Theodore F. |title = Japan at war: an oral history |edition=1st |year=1992 |publisher = New Press |location = New York |isbn=1-56584-014-3 |page=162 }}</ref> In a further parallel, the corpses of "sacrificed" subjects were disposed of by [[Cremation|incineration]].<ref name=":0">{{cite news |url = https://www.nytimes.com/1995/03/17/world/unmasking-horror-a-special-report-japan-confronting-gruesome-war-atrocity.html?pagewanted=all |title = Unmasking Horror – A special report. Japan Confronting Gruesome War Atrocity |newspaper = The New York Times |date = 17 March 1995 |access-date = April 10, 2017 |archive-date = January 20, 2018 |archive-url = https://web.archive.org/web/20180120034658/http://www.nytimes.com/1995/03/17/world/unmasking-horror-a-special-report-japan-confronting-gruesome-war-atrocity.html?pagewanted=all |url-status = live |last1 = Kristof |first1 = Nicholas D. }}</ref> Researchers in Unit&nbsp;731 also published some of their results in [[peer-reviewed journal]]s, writing as though the research had been [[Nonhuman primate experimentation|conducted on nonhuman primates]] called "Manchurian monkeys" or "long-tailed monkeys".<ref>{{Cite book |last=Harris |first=Sheldon H. |url=https://archive.org/details/factoriesofdeath0000harr/page/63 |title=Factories of death: Japanese biological warfare 1932 - 45 and the American cover-up |date=1999 |publisher=Routledge |isbn=978-0-415-13206-0 |edition=Reprint |location=London |page=63}}</ref>

At the age of 14, on the encouragement of a former school teacher, Hideo Shimizu joined the fourth group of minors assigned to Unit 731.<ref name="auto3">{{Cite web|url=https://www.asahi.com/ajw/articles/14988305|title=In twilight years, former Unit 731 member set on spreading truth {{pipe}} The Asahi Shimbun: Breaking News, Japan News and Analysis|work=The Asahi Shimbun }}</ref> He recalled that he was brought to a specimen room where jars of various heights, with some reaching the height of an adult, were stored.<ref name="auto3"/> The jars held body parts from humans preserved in [[formalin]], such as heads and hands.<ref name="auto3"/> There was also a pregnant woman's body with a large belly, where the lower part was exposed to reveal a fetus with hair. Shimizu discovered that the term "logs" was used dehumanizingly to refer to prisoners. He also learned that the prisoners were further dehumanized by being held in facilities referred to as "log cabins".<ref name="auto3"/>

=== Vivisection ===
Thousands of men, women, children, and infants interned at [[prisoner of war camps]] were subjected to [[vivisection]], often performed without [[anesthesia]] and usually lethal.<ref>Nicholas D. Kristof ''New York Times'', March 17, 1995. [https://query.nytimes.com/gst/fullpage.html?res=990CE2D71630F934A25750C0A963958260&sec=health&spon=&pagewanted=print "Unmasking Horror: A special report. Japan Confronting Gruesome War Atrocity"] {{Webarchive|url=https://web.archive.org/web/20110317115032/http://query.nytimes.com/gst/fullpage.html?res=990CE2D71630F934A25750C0A963958260&sec=health&spon=&pagewanted=print |date=2011-03-17 }}</ref><ref name="dissect">{{cite news |title=Dissect them alive: order not to be disobeyed |author=Richard Lloyd Parry |newspaper=Times Online |date=February 25, 2007 |url=http://www.timesonline.co.uk/tol/news/world/asia/article1438491.ece |location=London |access-date=February 26, 2007 |archive-date=May 23, 2011 |archive-url=https://web.archive.org/web/20110523225449/http://www.timesonline.co.uk/tol/news/world/asia/article1438491.ece }}</ref> In a video interview, former Unit&nbsp;731 member Okawa Fukumatsu admitted to having vivisected a pregnant woman.<ref name="vimeo1">{{cite web |title=(RARE) Unit 731 surgeon Okawa Fukumatsu (interview footage) |url=https://vimeo.com/manage/videos/625179260 |website=(RARE) Unit 731 surgeon Okawa Fukumatsu (interview footage) |access-date=2021-10-07 |archive-date=2021-10-07 |archive-url=https://web.archive.org/web/20211007074509/https://vimeo.com/manage/videos/625179260 |url-status=live }}</ref> Vivisections were performed on prisoners after infecting them with various diseases. Researchers performed [[Minimally invasive procedure#Invasive procedures|invasive surgery]] on prisoners, removing organs to study the effects of disease on the human body.<ref>{{cite web |title=Cognitive Dissonance, Social Psychology, and Unit 731|url=https://www.brandeis.edu/writing-program/write-now/2022-2023/yang-grace/index.html#about |website=Brandeis University |access-date=2025-09-16 |archive-date=21 July 2012 |archive-url=https://archive.today/20120721223501/http://top.rbc.ru/politics/26/11/2007/127141.shtml|url-status=live }}</ref>

Prisoners had limbs [[amputated]] in order to study [[Blood Loss|blood loss]]. Limbs removed were sometimes reattached to the opposite side of victims' bodies. Some prisoners had their stomachs surgically removed and their [[esophagus]] reattached to the [[Gastrointestinal tract|intestines]]. Parts of organs, such as the brain, lungs, and liver, were removed from others.<ref name="dissect"/> Imperial Japanese Army surgeon [[Ken Yuasa]] said that practising vivisection on human subjects was widespread even outside Unit&nbsp;731,<ref name="nyt">{{cite news |title=Unmasking Horror – A special report. Japan Confronting Gruesome War Atrocity |first=Nicholar D. |last=Kristof |date=17 March 1995 |newspaper=New York Times |url=https://www.nytimes.com/1995/03/17/world/unmasking-horror-a-special-report-japan-confronting-gruesome-war-atrocity.html?pagewanted=2 |access-date=20 February 2017 |archive-date=7 November 2017 |archive-url=https://web.archive.org/web/20171107115922/http://www.nytimes.com/1995/03/17/world/unmasking-horror-a-special-report-japan-confronting-gruesome-war-atrocity.html?pagewanted=2 |url-status=live }}</ref> estimating that at least 1,000 Japanese personnel were involved in the practice in mainland China.<ref>{{cite web|url=http://www.japantimes.co.jp/news/2007/10/24/reference/vivisectionist-recalls-his-day-of-reckoning/|title=Vivisectionist recalls his day of reckoning|first=Jun|last=Hongo|date=24 October 2007|via=Japan Times Online|access-date=16 May 2013|archive-date=1 April 2017|archive-url=https://web.archive.org/web/20170401172838/http://www.japantimes.co.jp/news/2007/10/24/reference/vivisectionist-recalls-his-day-of-reckoning//|url-status=live}}</ref> Yuasa said that when he performed vivisections on captives, they were "all for practice rather than for research", and that such practices were "routine" among Japanese doctors stationed in China during the war.<ref name=":0"/>

''[[The New York Times]]'' interviewed a former member of Unit 731. Insisting on anonymity, the former Japanese medical assistant recounted his first experience in vivisecting a live human being, who had been deliberately infected with the [[Plague (disease)|plague]], for the purpose of developing "plague bombs" for war. <blockquote>"The fellow knew that it was over for him, and so he didn't struggle when they led him into the room and tied him down, but when I picked up the scalpel, that's when he began screaming. I cut him open from the chest to the stomach, and he screamed terribly, and his face was all twisted in agony. He made this unimaginable sound, he was screaming so horribly. But then finally he stopped. This was all in a day's work for the surgeons, but it really left an impression on me because it was my first time."<ref>{{Cite news |last=Kristof |first=Nicholas D. |date=1995-03-17 |title=Unmasking Horror – A special report.; Japan Confronting Gruesome War Atrocity |language=en-US |work=The New York Times |url=https://www.nytimes.com/1995/03/17/world/unmasking-horror-a-special-report-japan-confronting-gruesome-war-atrocity.html |access-date=2023-01-03 |issn=0362-4331}}</ref></blockquote>

Other sources provided information on usual practice in the Unit for surgeons to stuff a rag (or medical gauze) into the mouth of prisoners before commencing vivisection in order to stifle any screaming.<ref>{{cite book |last1=Yang |first1=Yanjun |title=Japan's Biological Warfare in China |date=2016 |publisher=Foreign Language Press |location=Beijing |page=13}}</ref>

=== Biological warfare ===
[[File:Building on the site of the Harbin bioweapon facility of Unit 731 関東軍防疫給水部本部731部隊（石井部隊）日軍第731部隊旧址 PB121178a ボイラー楝跡.JPG|thumb|Ruins of a boiler building at the Unit&nbsp;731 [[bioweapon]]s facility]]

Unit&nbsp;731 and its affiliated units ([[Unit 1644]] and [[Unit 100]], among others) were involved in research, development and experimental deployment of epidemic-creating [[biological weapon]]s in assaults against the Chinese populace (both military and civilian) throughout World War&nbsp;II.<ref name="The day the earth died"/>

By 1939, Ishii had condensed his laboratory discoveries to six potent [[pathogen]]s: [[anthrax]], [[typhoid]], [[paratyphoid]], [[glanders]], [[dysentery]], and [[Plague (disease)|plague]]-infected human [[flea]]s. These agents were robust enough to ignite epidemics of considerable magnitude and resilient to aerial dispersal. This marked the initiation of the latter phase of Ishii's elaborate scheme: conducting field trials through military expeditions on unsuspecting civilians, aiming to devise a method of dissemination that would efficiently spread the pathogens in optimal concentrations for maximum devastation. His experiments involved the development of biodegradable bombs housing live rats and fleas infected with diseases, designed to explode mid-air, ensuring the safe descent of the infected creatures to the ground. Additionally, he deployed birds and bird feathers contaminated with anthrax from low-flying aircraft.<ref name="The day the earth died"/>

Plague-infected fleas, bred in the laboratories of Unit&nbsp;731 and Unit&nbsp;1644, were spread by low-flying airplanes over Chinese cities, including coastal [[Ningbo]] and [[Changde]], [[Hunan|Hunan Province]], in 1940 and 1941.<ref name="ciadoc" /> These operations killed tens of thousands with [[bubonic plague]] epidemics. An expedition to [[Nanjing]] involved spreading typhoid and paratyphoid germs into the [[well]]s, [[marsh]]es, and houses of the city, as well as infusing them in snacks distributed to locals. [[Epidemic]]s broke out shortly after, to the elation of many researchers, who concluded that [[paratyphoid fever]] was "the most effective" of the pathogens.<ref>{{Cite book |last=Harris |first=Sheldon H. |url=https://archive.org/details/factoriesofdeath0000harr/page/77 |title=Factories of death: Japanese biological warfare 1932 - 45 and the American cover-up |date=1999 |publisher=Routledge |isbn=978-0-415-13206-0 |edition=Reprint |location=London |page=77}}</ref><ref name="Barenblatt2004">Barenblatt, Daniel. ''A Plague Upon Humanity: the Secret Genocide of Axis Japan's Germ Warfare Operation'', HarperCollins, 2004. {{ISBN|0060186259}}.</ref>{{Rp|xii, 173}}

The [[Library of Congress]] holds a set of three declassified documents from Unit 731, each more than 100 pages long, translated from Japanese to English. These documents provided comprehensive clinical records about the daily progression of various pathogens within the bodies of helpless prisoners who were experimented on by Japanese doctors.<ref>{{cite book|title=Researching Japanese War Crimes|publisher=National Archives and Records Administration for the Nazi Warcrimes and Japanese Imperial Government Records Interagency Working Group|date=2006|page=17|last=Drea|first=Edward|url=https://www.archives.gov/files/iwg/japanese-war-crimes/introductory-essays.pdf}}</ref>

Japanese soldiers provided testimony indicating that the research program had the capability to manufacture substantial quantities of biological agents on a monthly basis: 300&nbsp;kg of plague, 500–700&nbsp;kg of anthrax, 800–900&nbsp;kg of typhoid, and 1,000&nbsp;kg of [[cholera]]. Despite the significant production volumes, even small amounts of these bacteria possessed the potential to cause severe harm and fatalities.<ref name="schulich.uwo.ca">{{Cite journal|last1=Johnson|first1=Kishor|title=A Scientific Method to the Madness of Unit 731's Human Experimentation and Biological Warfare Program|journal=Journal of the History of Medicine and Allied Sciences| url=https://www.schulich.uwo.ca/historymedicine/docs/Johnson_2021_JHMAS_Unit-731_Human-Experimentation.pdf|year=2021|volume=77|issue=1|pages=35–41|doi=10.1093/jhmas/jrab044|pmid=34897467 }}</ref>

Ishii determined that fleas were an efficient carrier for transmitting plague, leading Unit 731 to focus on breeding significant numbers of fleas. To achieve this goal, Unit 731 had approximately 4500 flea incubators, each capable of producing at least 45&nbsp;kg of fleas per cycle. The substantial quantities of plague bacteria and fleas generated, combined with the severe illness and death rates associated with plague infection, illustrate the formidable biological warfare production capabilities wielded by the Japanese. Japanese researchers had the required materials to apply the [[scientific method]] in conducting experiments involving [[inoculation]] and the creation of airborne bacterial bombs.<ref name="schulich.uwo.ca"/>

Food items emerged as the preferred delivery mechanism for bacterial transmission. The unit maintained a stock of uncontaminated fruits. In a specific experiment conducted by Unit 731, typhoid was introduced into melons and cantaloupes. Following the contamination process, the bacterial density was measured. Once reaching a density level, the infected fruit was distributed to a small group of prisoners, with the objective of spreading typhoid throughout the entire group.<ref name="schulich.uwo.ca"/>

Unit 731 conducted biological warfare field trials by attacking many Chinese civilian populations. During the period of 1940 to 1943, Japanese scientists found that using bacterial bombs for transmission was not effective, but they did find success in utilizing planes to spray microorganisms as a means of biological warfare delivery. Unit 100 also deployed aerial spraying methods akin to those examined by Unit 731.<ref name="schulich.uwo.ca"/>

At least 12 large-scale bioweapon field trials were carried out, and at least 11 Chinese cities attacked with biological agents. An attack on [[Changde]] in 1941 reportedly led to approximately 10,000 biological casualties and 1,700 deaths among ill-prepared Japanese troops, in most cases due to cholera.<ref>{{Cite book |last1=Williams |first1=Peter |title=Unit 731: Japan's secret biological warfare in World War II |last2=Wallace |first2=David |date=1989 |publisher=Free Press |isbn=978-0-02-935301-1 |edition=1st American |location=New York |pages=69–70}}</ref> Japanese researchers performed tests on prisoners with [[bubonic plague]], cholera, [[smallpox]], [[botulism]], and other diseases.<ref>[https://fas.org/nuke/guide/japan/bw/ Biological Weapons Program-Japan] {{Webarchive|url=https://web.archive.org/web/20100727172723/http://www.fas.org/nuke/guide/japan/bw/ |date=2010-07-27 }} Federation of American Scientists</ref> This research led to the development of the [[defoliation bacilli bomb]] and the flea bomb used to spread bubonic plague.<ref>[http://www.centurychina.com/wiihist/germwar/731rev.htm Review of the studies on Germ Warfare] {{Webarchive|url=https://web.archive.org/web/20121119074840/http://www.centurychina.com/wiihist/germwar/731rev.htm |date=2012-11-19 }} Tien-wei Wu ''A Preliminary Review of Studies of Japanese Biological Warfare and Unit 731 in the United States''</ref> Some of these bombs were designed with [[porcelain]] shells, an idea proposed by Ishii in 1938.

These bombs enabled Japanese soldiers to launch biological attacks, infecting agriculture, [[reservoir]]s, wells, as well as other areas, with [[anthrax]]- and [[Bubonic plague|plague]]-carrier fleas, [[typhoid]], cholera, or other deadly pathogens. During biological bomb experiments, researchers dressed in protective suits would examine the dying victims. Infected food supplies and clothing were dropped by airplane into areas of China not occupied by Japanese forces. In addition, poisoned food and candy were given to unsuspecting victims. [[Bubonic Plague|Plague]] fleas, infected clothing, and infected supplies encased in bombs were dropped on various targets. The resulting [[cholera]], [[anthrax]], and plague were estimated to have killed at least 400,000 Chinese civilians.<ref>{{cite book |last1=Barenblatt |first1=Daniel |title=A Plague upon Humanity: The Secret Genocide of Axis Japan's Germ Warfare Operation |date=2004 |publisher=Harper |location=New York|isbn=978-0-06-018625-8 |pages=[https://archive.org/details/plagueuponhumani00bare/page/163 163–175] |edition=1 |url=https://archive.org/details/plagueuponhumani00bare/page/163 }}</ref> [[Tularemia]] was also tested on Chinese civilians.<ref>[http://ftp.cdc.gov/pub/epr/historyofbt/wmcc/07_tularemia_cc.wmv Video] {{Webarchive|url=https://web.archive.org/web/20170921143738/https://ftp.cdc.gov/pub/epr/historyofbt/wmcc/07_tularemia_cc.wmv |date=2017-09-21 }} adapted from "Biological Warfare & Terrorism: The Military and Public Health Response", [[Centers for Disease Control and Prevention]]. Retrieved October 21, 2007</ref>

Due to pressure from numerous accounts of the biowarfare attacks, [[Chiang Kai-shek]] sent a delegation of army and foreign medical personnel in November&nbsp;1941 to document evidence and treat the afflicted. A report on the Japanese use of plague-infected fleas on Changde was made widely available the following year but was not addressed by the Allied Powers until [[Franklin D. Roosevelt]] issued a public warning in 1943 condemning the attacks.<ref>{{cite web|title=Biohazard: Unit 731 and the American Cover-Up|page=5|url=https://www.umflint.edu/sites/default/files/groups/Research_and_Sponsored_Programs/MOM/b.altheide.pdf|website=[[University of Michigan–Flint]]|access-date=2019-05-31|archive-date=2019-07-31|archive-url=https://web.archive.org/web/20190731012542/https://www.umflint.edu/sites/default/files/groups/Research_and_Sponsored_Programs/MOM/b.altheide.pdf}}</ref><ref>{{Cite book|last=Guillemin|first=Jeanne|title=One Hundred Years of Chemical Warfare: Research, Deployment, Consequences |chapter=The 1925 Geneva Protocol: China's CBW Charges Against Japan at the Tokyo War Crimes Tribunal |date=2017|editor-last=Friedrich|editor-first=Bretislav|editor2-last=Hoffmann|editor2-first=Dieter|editor3-last=Renn|editor3-first=Jürgen|editor4-last=Schmaltz|editor4-first=Florian|editor5-last=Wolf|editor5-first=Martin|language=en|publisher=Springer International Publishing|pages=273–286|doi=10.1007/978-3-319-51664-6_15|isbn=978-3-319-51664-6|doi-access=free}}</ref>

In December 1944, the Japanese Navy explored the possibility of attacking cities in California with biological weapons, known as [[Operation PX]] or Operation Cherry Blossoms at Night. The plan for the attack involved [[Aichi M6A|''Seiran'']] aircraft launched by Sentoku [[I-400-class submarine|submarine aircraft carriers]] upon the West Coast of the United States—specifically, the cities of San Diego, Los Angeles, and San Francisco. The planes would spread weaponized [[bubonic plague]], [[cholera]], [[typhus]], [[dengue fever]], and other pathogens in a biological terror attack upon the population. The submarine crews would infect themselves and run ashore in a suicide mission.<ref>Garrett, Benjamin C. and John Hart. ''Historical Dictionary of Nuclear, Biological and Chemical Warfare'', page 159.</ref><ref>Geoghegan, John. ''Operation Storm: Japan's Top Secret Submarines and Its Plan to Change the Course of World War II'', pages 189–191.</ref><ref>Gold, Hal. Unit 731 Testimony: Japan's Wartime Human Experimentation Program, pages 89–92</ref><ref>{{cite news |last=Kristoff |first=Nicholas D. |date=March 17, 1995 |title=Unmasking Horror -- A special report.; Japan Confronting Gruesome War Atrocity |url=https://www.nytimes.com/1995/03/17/world/unmasking-horror-a-special-report-japan-confronting-gruesome-war-atrocity.html |newspaper=The New York Times |access-date=August 6, 2015 }}</ref> Planning for Operation PX was finalized on March 26, 1945, but shelved shortly thereafter due to the strong opposition of Chief of General Staff [[Yoshijirō Umezu]]. Umezu later explained his decision as such: "If bacteriological warfare is conducted, it will grow from the dimension of war between Japan and America to an endless battle of humanity against bacteria. Japan will earn the derision of the world."<ref>Felton, Mark. ''The Devil's Doctors: Japanese Human Experiments on Allied Prisoners of War'', Chapter 10</ref>

=== Weapons testing ===
Human targets were used to test [[grenade]]s positioned at various distances and in various positions. [[Flamethrower]]s were tested on people.<ref>{{cite journal |last1=Hickey |first1=Doug |last2=Li |first2=Scarllet Sijia |last3=Morrison |first3=Ceila |last4=Schulz |first4=Richard |last5=Thiry |first5=Michelle |last6=Sorensen |first6=Kelly |date=April 2017 |title=Unit 731 and Moral Repair |doi=10.1136/medethics-2015-103177 |journal=Journal of Medical Ethics |volume=43 |issue=4 |pages=270–276|pmid=27003420 |s2cid=20475762 }}</ref> Victims were also tied to stakes and used as targets to test [[Germ warfare|pathogen-releasing bombs]], [[chemical weapon]]s, shrapnel bombs with varying amounts of fragments, and explosive bombs as well as [[bayonet]]s and knives.

{{Blockquote|To determine the best course of treatment for varying degrees of shrapnel wounds sustained on the field by Japanese Soldiers, Chinese prisoners were exposed to direct bomb blasts. They were strapped, unprotected, to wooden planks that were staked into the ground at increasing distances around a bomb that was then detonated. It was surgery for most, autopsies for the rest.|Unit 731, Nightmare in Manchuria<ref>Monchinski, Tony (2008). ''Critical Pedagogy and the Everyday Classroom''. Volumen 3 de Explorations of Educational Purpose. Springer, p. 57. {{ISBN|1402084625}}</ref><ref>Neuman, William Lawrence (2008). ''Understanding Research''. Pearson/Allyn and Bacon, p. 65. {{ISBN|0205471536}}</ref>}}

=== Frostbite testing ===
[[File:Scan Of Yoshimura Hisato's Frostbite Research Data.png|thumb|Scan of [[Yoshimura Hisato]]'s [[frostbite]] research data]]

Army Engineer Hisato Yoshimura<!--Yoshimura is the family name as per http://www.lit.osaka-cu.ac.jp/user/tsuchiya/gyoseki/presentation/UNESCOkumamoto07.html, but this article should generally use Western order for Japanese people.--> conducted experiments by taking captives outside, dipping various appendages into water of varying temperatures, and allowing the [[Frostbite|limb to freeze]].<ref>{{cite web|url=http://www.lit.osaka-cu.ac.jp/user/tsuchiya/gyoseki/presentation/UNESCOkumamoto07.html|title=Self Determination by Imperial Japanese Doctors|website=www.lit.osaka-cu.ac.jp|access-date=2019-05-31|archive-date=2019-05-31|archive-url=https://web.archive.org/web/20190531063454/http://www.lit.osaka-cu.ac.jp/user/tsuchiya/gyoseki/presentation/UNESCOkumamoto07.html|url-status=live}}</ref> Once frozen, Yoshimura would strike their affected limbs with a short stick, "emitting a sound resembling that which a board gives when it is struck".<ref name="Kristor" /> Ice was then chipped away, with the affected area being subjected to various treatments. Military personnel of the Unit referred to Yoshimura as a "scientific devil" and a "cold-blooded animal" due to his strictness and involvement in mass killings and inhumane scientific tests, which included soaking the fingers of a three-day-old child in water containing ice and salt.<ref>{{cite book |last1=LaFleur| url=https://books.google.com/books?id=gGQYOvo9-AsC&q=Yoshimura+ |first1=William |last2=Böhme |first2=Gernot |last3=Shimazono |first3=Susumu |title=Dark medicine: rationalizing unethical medical research |date=2007 |publisher=Indiana University Press|pages=76–77 |location=US| isbn=978-0-253-22041-7 }}</ref>

Naoji Uezono, a member of Unit 731, described in a 1980s interview a grisly scene where Yoshimura had "two naked men put in an area 40–50 degrees below zero and researchers filmed the whole process until [the subjects] died. [The subjects] suffered such agony they were digging their nails into each other's flesh."<ref>{{cite book |last1=Emanuel |first1=Ezekiel |last2=Grady |first2=Christine |last3=Crouch |first3=Robert |last4=Lie |first4=Reidar |last5=Miller |first5=Franklin |title=The Oxford Textbook of Clinical Research Ethics |date=2011 |publisher=Oxford University Press |location=US|page=36}}</ref> Yoshimura's lack of remorse was evident in an article he wrote for the Japanese Journal of Physiology in 1950 in which he admitted to using 20 children and a three-day-old infant in experiments which exposed them to zero-degree-Celsius ice and salt water.<ref>{{cite book |last1=Yoshimura |first1=Hisato |last2=Iida |first2=Toshiyuki |title=Studies on the Reactivity of Skin Vessels to Extreme Cold |date=1950 |publisher=Japanese Journal Of Physiology |location=Japan}}</ref> Although this article drew criticism, Yoshimura denied any guilt when contacted by a reporter from the ''[[Mainichi Shimbun]]''.<ref>{{cite book |last1=Kei-ichi |first1=Tsuneishi |last2=Asano |first2=Tomizo |title=Kieta saikin-sen butai to jiketsu shita futari no igakusha |script-title=ja:消えた細菌戦部隊と自決した二人の医学者|trans-title=The biological warfare unit and two physicians who committed suicide |language=ja |date=1982 |publisher=Shinchosha |location=Tokyo |isbn=978-4-10-344001-7}}</ref>

Yoshimura developed a "resistance index of frostbite" based on the mean temperature 5 to 30&nbsp;minutes after immersion in freezing water, the temperature of the first rise after immersion, and the time until the temperature first rises after immersion. In a number of separate experiments it was then determined how these parameters depend on the time of day a victim's body part was immersed in freezing water, the surrounding temperature and humidity during immersion, how the victim had been treated before the immersion ("after keeping awake for a night", "after hunger for 24 hours", "after hunger for 48 hours", "immediately after heavy meal", "immediately after hot meal", "immediately after muscular exercise", "immediately after cold bath", "immediately after hot bath"), what type of food the victim had been fed over the five days preceding the immersions with regard to dietary nutrient intake ("high protein (of animal nature)", "high protein (of vegetable nature)", "low protein intake", and "standard diet"), and salt intake (45&nbsp;g NaCl per day, 15&nbsp;g NaCl per day, no salt).<ref>{{cite book |last1=Eckart |first1=Wolfgang |title=Man, Medicine, and the State: The Human Body as an Object of Government Sponsored Medical Research in the 20th Century |date=2006 |publisher=Franz Steiner Verlag |page=191}}</ref> This original data is seen in the attached figure.

=== Syphilis ===
Unit members orchestrated forced sex acts between infected and non-infected prisoners to transmit the disease, as the testimony of a prison guard on the subject of devising a method for transmission of [[syphilis]] between victims shows:

{{blockquote|Infection of venereal disease by injection was abandoned, and the researchers started forcing the prisoners into sexual acts with each other. Four or five unit members, dressed in white laboratory clothing completely covering the body with only eyes and mouth visible, rest covered, handled the tests. A male and female, one infected with syphilis, would be brought together in a cell and forced into sex with each other. It was made clear that anyone resisting would be shot.<ref name="gold-testimony"/>}}

After victims were infected, they were vivisected at different stages of infection, so that internal and external organs could be observed as the disease progressed. Testimony from multiple guards blames the female victims as being hosts of the diseases, even as they were forcibly infected. Genitals of female prisoners that were infected with syphilis were called "jam-filled buns" by guards.<ref name="gold-testimony"/>

Some children grew up inside the walls of Unit&nbsp;731, infected with syphilis. A Youth Corps member deployed to train at Unit&nbsp;731 recalled viewing a batch of subjects that would undergo syphilis testing: "one was a Chinese woman holding an infant, one was a [[White émigré#In China|White Russian]] woman with a daughter of four or five years of age, and the last was a White Russian woman with a boy of about six or seven."<ref name="gold-testimony"/> The children of these women were tested in ways similar to their parents, with specific emphasis on determining how longer infection periods affected the effectiveness of treatments.

=== Rape and forced pregnancy ===
Female prisoners were forced to become pregnant for use in experiments. The hypothetical possibility of [[vertical transmission]] (from mother to child) of diseases, particularly syphilis, was the stated reason for the torture. Fetal survival and damage to mother's reproductive organs were objects of interest. Though "a large number of babies were born in captivity", there have been no accounts of any survivors of Unit&nbsp;731, children included. It is suspected that the children of female prisoners were killed after birth or [[Abortion|aborted]].<ref name="gold-testimony"/>

While male prisoners were often used in single studies, so that the results of the experimentation on them would not be clouded by other variables, women were sometimes used in bacteriological or physiological experiments, sex experiments, and as the victims of [[sex crimes]]. The testimony of a unit member that served as a guard graphically demonstrated this reality:

{{blockquote|One of the former researchers I located told me that one day he had a human experiment scheduled, but there was still time to kill. So he and another unit member took the keys to the cells and opened one that housed a Chinese woman. One of the unit members raped her; the other member took the keys and opened another cell. There was a Chinese woman in there who had been used in a frostbite experiment. She had several fingers missing and her bones were black, with [[gangrene]] set in. He was about to rape her anyway, then he saw that her sex organ was festering, with [[pus]] oozing to the surface. He gave up the idea, left and locked the door, then later went on to his experimental work.<ref name="gold-testimony"/>}}

=== Other experiments ===

Unit 731 conducted a wide range of experiments beyond biological warfare, many involving torture, chemical exposure, and physiological manipulation. The following categories summarize the types of experiments carried out.

==== Physical and environmental torture ====

Prisoners were subjected to extreme methods of physical stress, including:
* Prolonged starvation and dehydration;
* Exposure to low-pressure chambers until their eyes burst;
* Suspension upside down until death;
* [[Crushed to death|Crushing with heavy objects]];
* [[Electrocution]];
* Forced dehydration using hot air fans;<ref>Dwight R. Rider, [http://www.mansell.com/Resources/Rider_Whos_Who_in_Japanese_BW_2018-10-09_IN_PROCESS--SEEK-PERMISSION-TO-USE.pdf ''Japan's Biological and Chemical Weapons Programs; War Crimes and Atrocities: Who's Who, What's What and Where's Where – 1928–1945''], 3rd ed., 14 November 2018, p. 119. {{Webarchive|url=https://web.archive.org/web/20211101094710/http://www.mansell.com/Resources/Rider_Whos_Who_in_Japanese_BW_2018-10-09_IN_PROCESS--SEEK-PERMISSION-TO-USE.pdf |date=1 November 2021}}</ref>
* Spinning in [[centrifuge]]s until death;
* Exposure to extreme heat and burns;
* Injection with animal blood, including horse blood;
* Injection with seawater;
* [[Death by burning|Burning]] or [[Premature burial|live burial]].<ref>{{cite news |last=Silvester |first=Christopher |title=Electrocuted, gassed, frozen, boiled alive |url=https://www.telegraph.co.uk/culture/books/3651939/Electrocuted-gassed-frozen-boiled-alive.html |work=Daily Telegraph |date=29 April 2006 |access-date=31 May 2019 |archive-url=https://ghostarchive.org/archive/20220110/https://www.telegraph.co.uk/culture/books/3651939/Electrocuted-gassed-frozen-boiled-alive.html |archive-date=10 January 2022 |url-status=live |language=en-GB |issn=0307-1235}}</ref><ref name="aiipowmia">{{cite web |url=http://www.aiipowmia.com/731/731holocaust.html |title=The Nanjing Massacre and Unit 731 |year=2001 |publisher=Advocacy & Intelligence Index For POWs-MIAs Archives |access-date=28 September 2010 |archive-url=https://web.archive.org/web/20071017024440/http://www.aiipowmia.com/731/731holocaust.html |archive-date=17 October 2007}}</ref>

Dehydration experiments aimed to measure total body water content and survival duration without water. Victims were often starved before testing. Staff documented their physical decline at regular intervals.

{{Blockquote|text="It was said that a small number of these poor men, women, and children who became marutas were also mummified alive in total dehydration experiments. They sweated themselves to death under the heat of several hot dry fans. At death, the corpses would only weigh ≈1/5 normal bodyweight."|source=Hal Gold, ''Japan's Infamous Unit 731'' (2019)}}

==== Chemical and toxin exposure ====

Victims were exposed to a wide range of toxic agents including:
* [[Mustard gas]];
* [[Lewisite]];
* Cyanic acid gas;
* [[White phosphorus]];
* [[Adamsite]];
* [[Phosgene]].

Unit 731 operated a facility dedicated to gas chamber experiments. Victims were placed in sealed chambers wearing either full uniform, partial gear, or no protection. A former army major and later [[Emeritus|professor emeritus]] recalled:

{{Blockquote|text=In 1943, I attended a poison gas test held at the Unit 731 test facilities. A glass-walled chamber about three meters square [{{convert|9|m2|sqft|disp=out}}] and two meters [{{convert|2|m|ft|disp=out}}] high was used. Inside of it, a Chinese man was blindfolded, with his hands tied around a post behind him. The gas was adamsite (sneezing gas), and as the gas filled the chamber the man went into violent coughing convulsions and began to suffer excruciating pain. More than ten doctors and technicians were present. After I had watched for about ten minutes, I could not stand it any more, and left the area. I understand that other types of gasses were also tested there.|source=Hal Gold, ''Japan's Infamous Unit 731'', p. 349 (2019)}}

==== Field testing ====

Unit 731 conducted field trials of chemical weapons. A report from the Kamo Unit described yperite (mustard gas) experiments on 7–10 September 1940 involving 20 prisoners in various clothing conditions. Subjects were exposed to up to 4,800 artillery rounds. Symptoms were documented at multiple intervals. In one case, fluid from blisters was injected into other subjects, and blood and stool were analyzed. Five prisoners were forced to drink yperite–lewisite solutions.

{{Blockquote|text=Number 376, dugout of the first area:

September 7, 1940, 6 pm: Tired and exhausted. Looks with hollow eyes. Weeping redness of the skin of the upper part of the body. Eyelids edematous, swollen. Epiphora. Hyperemic conjunctivae.

September 8, 6 am: Neck, breast, upper abdomen and scrotum weeping, reddened, swollen. Covered with millet-seed-size to bean-size blisters. Eyelids and conjunctivae hyperemic and edematous. Had difficulties opening the eyes.

September 8, 6 pm: Tired and exhausted. Feels sick. Body temperature 37°C. Mucous and bloody erosions across the shoulder girdle. Abundant mucous nose secretions. Abdominal pain. Mucous and bloody diarrhea. Proteinuria.

September 9, 7 am: Tired and exhausted. Weakness of all four extremities. Low morale. Body temperature 37°C. Skin of the face still weeping.|source=''Man, Medicine, and the State: The Human Body as an Object of Government Sponsored Medical Research in the 20th Century'' (2006), p. 187}}

==== Blood and toxin research ====

Unit 731 studied blood loss and incompatible blood transfusions. Former member Okawa Fukumatsu stated that some prisoners had 500 ml of blood withdrawn every two to three days.<ref>{{cite book |last=Gold |first=Hal |title=Japan's Infamous Unit 731 |year=2019 |publisher=Tuttle Publishing |location=Japan}}</ref>

Experiments with incompatible [[blood type]]s were conducted. Unit member Naeo Ikeda recorded:

{{Blockquote|text=In my experience, when A type blood 100 cc was transfused to an O type subject, whose pulse was 87 per minute and temperature was 35.4 degrees C, 30 minutes later the temperature rose to 38.6 degrees with slight trepidation. Sixty minutes later the pulse was 106 per minute and the temperature was 39.4 degrees. Two hours later the temperature was 37.7 degrees, and three hours later the subject recovered. When AB type blood 120 cc was transfused to an O type subject, an hour later the subject described malaise and psychroesthesia in both legs. When AB type blood 100 cc was transfused to a B type subject, there seemed to be no side effect.|source=''Man, Medicine, and the State: The Human Body as an Object of Government Sponsored Medical Research in the 20th Century'' (2006), pp. 38–39}}

Prisoners were also exposed to biological toxins including [[tetrodotoxin]] (from [[Tetraodontidae|pufferfish]]), [[heroin]], Korean bindweed, bactal, and [[castor oil]] seeds (containing [[ricin]]).<ref>{{cite book |last1=Croddy |first1=Eric |last2=Wirtz |first2=James |title=Weapons of Mass Destruction: Chemical and Biological Weapons |year=2005 |publisher=ABC-CLIO |isbn=978-1-85109-490-5}}</ref><ref name="trialmaterials" />

==== Other accounts ====

Former medical worker Takeo Wano claimed to have seen a Western man, believed to be Russian, cut in half vertically and preserved in [[formaldehyde]].<ref name="Kristor">{{cite news |last=Kristof |first=Nicholas D. |title=Unmasking Horror – A Special Report: Japan Confronting Gruesome War Atrocity |url=https://www.nytimes.com/1995/03/17/world/unmasking-horror-a-special-report-japan-confronting-gruesome-war-atrocity.html |work=The New York Times |date=17 March 1995 |access-date=28 April 2022}}</ref>

Unit 100 reportedly used portable [[gas chamber]]s for testing. Victims wore military clothing, gas masks, or nothing at all. Some experiments lacked any military rationale. For instance, one documented test measured how long it took for three-day-old babies to freeze to death.<ref>{{cite web |date=24 November 2013 |title=Inside Japan's wartime factory of death |url=http://benhills.com/articles/the-war/inside-japans-wartime-factory-of-death/ |access-date=31 May 2019 |website=Ben Hills |language=en-GB |archive-date=31 May 2019 |archive-url=https://web.archive.org/web/20190531063452/http://benhills.com/articles/the-war/inside-japans-wartime-factory-of-death/ |url-status=live}}</ref><ref>{{cite web |date=17 December 1994 |title=Asia's Auschwitz |url=https://www.smh.com.au/world/asias-auschwitz-19941217-gdfkwq.html |access-date=27 October 2020 |website=The Sydney Morning Herald |language=en |archive-date=30 October 2020 |archive-url=https://web.archive.org/web/20201030225648/https://www.smh.com.au/world/asias-auschwitz-19941217-gdfkwq.html |url-status=live}}</ref>

== Prisoners and victims ==

After Japan's defeat in World War II, the Japanese murdered every single prisoner in the unit. The remains were then buried in the Unit 731 grounds after being cremated.<ref name="books.google.com">{{cite book |last1=LaFleur| url=https://books.google.com/books?id=gGQYOvo9-AsC&q=Yoshimura+ |first1=William |last2=Böhme |first2=Gernot |last3=Shimazono |first3=Susumu |title=Dark medicine: rationalizing unethical medical research |date=2007 |publisher=Indiana University Press|page=77 |location=US| isbn=978-0-253-22041-7 }}</ref> The following testimony explains how the captives were murdered:
<blockquote>
On August 11 and 12, after the end of the war, approximately 300 prisoners were disposed of. The prisoners were coerced into suicide by being given a piece of rope. One quarter of them hung themselves, and the remaining three quarters who would not consent to suicide were made to drink potassium cyanide and killed by injection. In the end all were taken care of. The prisoners were made to drink potassium cyanide by mixing it with water and putting it into bowls. The injections were most likely chloroform.<ref name="books.google.com"/></blockquote>

In 2002, [[Changde]], China, site of the plague flea bombing, held an "International Symposium on the Crimes of Bacteriological Warfare," which estimated that the number of people slaughtered by the [[Imperial Japanese Army]] germ warfare and other human experiments was around 580,000.<ref name="Barenblatt2004" />{{Rp|xii, 173}} The American historian [[Sheldon H. Harris]] states that over 200,000 died.<ref>{{Cite book |last1=Gow |first1=James |url=https://books.google.com/books?id=iX-YDwAAQBAJ&q=harris+200000+biological+warfare&pg=PT333 |title=Routledge Handbook of War, Law and Technology |last2=Dijxhoorn |first2=Ernst |last3=Kerr |first3=Rachel |last4=Verdirame |first4=Guglielmo |date=2019 |publisher=Routledge |isbn=978-1-351-61997-4 |pages=239, 246 |language=en |access-date=2020-11-22 |archive-url=https://web.archive.org/web/20210414162826/https://books.google.com/books?id=iX-YDwAAQBAJ&q=harris+200000+biological+warfare&pg=PT333 |archive-date=2021-04-14 |url-status=live}}</ref><ref name="Kristof" /> In addition to Chinese casualties, 1,700 Japanese troops in [[Zhejiang]] during [[Zhejiang-Jiangxi campaign]] were killed by their own biological weapons while attempting to unleash the biological agent, indicating serious issues with distribution.<ref name="dcr">David C. Rapoport. "Terrorism and Weapons of the Apocalypse". In James M. Ludes, Henry Sokolski (eds.), ''Twenty-First Century Weapons Proliferation: Are We Ready?'' Routledge, 2001. pp. 19, 29</ref> Harris also said plague-infected animals were released near the end of the war, and caused plague outbreaks that killed at least 30,000 people in the Harbin area from 1946 to 1948.<ref name="Kristof"/>

Some test subjects were selected to gather a wide cross-section of the population and included common criminals, captured bandits, anti-Japanese [[partisan (military)|partisans]], [[political prisoners in Imperial Japan|political prisoners]], [[homeless]] and [[mentally disabled]] people, which included infants, men, the elderly and pregnant women, as well as those rounded up by the ''[[Kenpeitai]]'' military police for alleged "suspicious activities". Unit&nbsp;731 staff included approximately 300 researchers, including doctors and [[bacteriologist (Professional)|bacteriologists]].<ref>{{Cite book |last=Harris |first=Sheldon H. |url=https://archive.org/details/factoriesofdeath0000harr/page/334 |title=Factories of death: Japanese biological warfare 1932 - 45 and the American cover-up |date=1999 |publisher=Routledge |isbn=978-0-415-13206-0 |edition=Reprint |location=London |page=334}}</ref>

At least 3,000 men, women, and children<ref name="trialmaterials" />{{rp|117}}<ref name="dcr"/>—of which at least 600 every year were provided by the ''Kenpeitai''<ref>Yuki Tanaka, ''Hidden Horrors'', Westviewpress, 1996, p. 138</ref>—were subjected to Unit&nbsp;731 experimentation conducted at the [[Pingfang District|Pingfang]] camp alone, not including victims from other medical experimentation sites such as [[Unit 100]].<ref>{{cite web|url=http://www.lit.osaka-cu.ac.jp/user/tsuchiya/gyoseki/presentation/IAB8.html|title=[IAB8] Imperial Japanese Medical Atrocities|work=osaka-cu.ac.jp|access-date=2016-10-02|archive-date=2016-03-04|archive-url=https://web.archive.org/web/20160304043000/http://www.lit.osaka-cu.ac.jp/user/tsuchiya/gyoseki/presentation/IAB8.html|url-status=live}}</ref> Although 3,000 internal victims is the widely accepted figure in the literature, former Unit member Okawa Fukumatsu claims that there were at least 10,000 victims of internal experiments at the Unit, he himself [[Vivisection|vivisecting]] thousands.<ref name="vimeo1"/>

According to A. S. Wells, the majority of victims were [[Chinese people|Chinese]],{{r|nyt}} with a lesser percentage being [[White émigré|Russian]], [[Mongols|Mongolian]], and [[Koreans|Korean]]. They may also have included a small number of European, American, Indian, Australian, and New Zealander [[Prisoner of war|prisoners of war]] (see also [[Allied prisoners of war in Japan]]).<ref name="Wells 2009 p. 42">{{cite book | last=Wells | first=A. S. | title=The A to Z of World War II: The War Against Japan | publisher=Scarecrow Press | series=The A to Z Guide Series | year=2009 | isbn=978-0-8108-7026-0 | url=https://books.google.com/books?id=_ptE9EGO_WUC&pg=PA42 | access-date=2017-07-08 | page=42 | archive-date=2022-06-07 | archive-url=https://web.archive.org/web/20220607180427/https://books.google.com/books?id=_ptE9EGO_WUC | url-status=live }}</ref><ref>[https://web.archive.org/web/20071217155553/http://www.cc.matsuyama-u.ac.jp/~tamura/731butai.htm The devil unit, Unit 731. 731部隊について], accessed 17 Dec 2007</ref><ref>{{cite web|url=http://www.chinafile.com/library/nyrb-china-archive/north-korea-wonder-terror|title=In North Korea: Wonder & Terror|last=Buruma|first=Ian|date=4 June 2015|work=www.chinafile.com|publisher=The New York Review of Books|access-date=11 November 2016|archive-date=16 January 2018|archive-url=https://web.archive.org/web/20180116002323/http://www.chinafile.com/library/nyrb-china-archive/north-korea-wonder-terror|url-status=live}}</ref> A member of the [[Yokusan Sonendan]] [[paramilitary]] political youth branch, who worked for Unit&nbsp;731, stated that not only were Chinese, Russians, and Koreans present, but also Americans, British, and French people.<ref>{{cite book|last1=Gold|first1=Hal|title=Japan's Infamous Unit 731: First-hand Accounts of Japan's Wartime Human Experimentation Program |year=2019|publisher=Tuttle Publishing|location=United States|isbn=978-0-8048-5219-7|pages=169–170|last2=Totani|first2=Yuma.}}</ref> Sheldon H. Harris documented that the victims were generally [[Political dissent|political dissidents]], communist sympathizers, ordinary criminals, impoverished civilians, and the mentally disabled.<ref>{{cite web|url=http://www.vcn.bc.ca/alpha/speech/Harris.htm|title=Japanese Medical Atrocities in World War II|website=www.vcn.bc.ca|access-date=2019-05-10|archive-date=2019-06-18|archive-url=https://web.archive.org/web/20190618203650/http://www.vcn.bc.ca/alpha/speech/Harris.htm|url-status=live}}</ref> Author [[Seiichi Morimura]] estimates that almost 70 percent of the victims who died in the Pingfang camp were Chinese (both military and civilian),<ref>{{cite web|url=http://www1.korea-np.co.jp/sinboj/sinboj2002/8/0826/81.htm|title=旧日本軍の731部隊（細菌部隊）人体実験に朝鮮人|work=korea-np.co.jp|archive-url=https://web.archive.org/web/20150813034434/http://www1.korea-np.co.jp/sinboj/sinboj2002/8/0826/81.htm|archive-date=2015-08-13}}</ref> while close to 30 percent of the victims were Russian.<ref>{{cite web|url=http://www.x-libri.ru/elib/morim000/00000036.htm|title=Часть 36 из 150 – Моримура Сэйити. Кухня дьявола|website=www.x-libri.ru|access-date=2016-10-02|archive-date=2014-09-06|archive-url=https://web.archive.org/web/20140906073729/http://www.x-libri.ru/elib/morim000/00000036.htm|url-status=live}}</ref>

[[File:A sketch of the prison cells, done by a member of Unit 731. The octagonal sketch represents the pressure chamber.jpg|thumb|A sketch of the prison cells drawn by a Unit&nbsp;731 staff member. The [[octagon]] represents the [[pressure chamber]].]]

No one who entered Unit&nbsp;731 came out alive. Prisoners were usually received into Unit&nbsp;731 at night in motor vehicles painted black with a [[Ventilation (architecture)|ventilation hole]] but no windows.<ref name="trialmaterials" />{{rp|112}} The vehicle would pull up at the main gates and one of the drivers would go to the guardroom and report to the guard. That guard would then telephone to the "Special Team" in the inner-prison ([[Shirō Ishii]]'s brother was head of this Special Team).<ref name="auto2">{{cite book |last1=Gold |first1=Hal |title=Japan's Infamous Unit 731 |date=2019 |publisher=Tuttle Publishing |location=Japan |page=306}}</ref><ref name="trialmaterials" />{{rp|366}} Then, the prisoners would be transported through a secret tunnel dug under the facade of the central building to the inner-prisons.<ref name="trialmaterials" />{{rp|117}} One of the prisons housed women and children (Building&nbsp;8), while the other prison housed men (Building&nbsp;7). Once at the inner-prison, technicians would take samples of the prisoners' blood and stool, test their [[Assessment of kidney function|kidney function]], and collect other physical data.<ref>{{cite book |last1=Gold |first1=Hal |title=Japan's Infamous Unit 731 |date=2019 |publisher=Tuttle Publishing |location=Japan |page=311}}</ref> Once deemed healthy and fit for experimentation, prisoners lost their names and were given a three-digit number, which they retained until their death. Whenever prisoners died after the experiments they had been subjected to, a clerk of the 1st&nbsp;Division struck their numbers off an index card and took the deceased prisoner's [[manacles]] to be put on new arrivals to the prison.<ref name="trialmaterials" />{{rp|427}}

There is at least one recorded instance of "friendly" social interaction between prisoners and Unit&nbsp;731 staff. Technician Naokata Ishibashi interacted with two female prisoners, a 21-year-old Chinese woman and a 19-year-old [[Ukraine|Ukrainian]] woman. The two prisoners told Ishibashi that they had not seen their faces in a mirror since being captured and begged him to get one. Ishibashi snuck a mirror to them through a hole in the cell door.<ref>{{cite book |last1=Gold |first1=Hal |title=Japan's Infamous Unit 731 |date=2019 |publisher=Tuttle Publishing |location=Japan |page=317}}</ref>

The prison cells had wooden floors and a [[squat toilet]] in each. There was space between the outer walls of the cells and the outer walls of the prison, enabling the guards to walk behind the cells. Each cell door had a small window in it. Chief of the Personnel Division of the Kwantung Army Headquarters Tamura Tadashi testified that, when he was shown the inner-prison, he looked into the cells and saw living people in chains, some moved around, others were lying on the bare floor and were in a very sick and helpless condition.<ref name="trialmaterials" />{{rp|349,450}} The inner-prison was a highly secured building complete with cast iron doors.<ref name="auto2"/> The "special team" worked in these two inner-prison buildings. This team wore white overall suits, army hats, rubber boots, and pistols strapped to their sides.<ref name="auto2"/>

===Escape attempts===
Despite the prison's status as a highly secure building, at least two unsuccessful escape attempts did occur.

The first attempt occurred between May and June 1943 and involved one of the prisoners knocking out an inattentive guard and stealing his keys. The prisoner then proceeded to open cell doors, freeing at least 100 prisoners. However, the prisoners remained confined to the inner courtyard of the prison building, from which they could not escape. Because the researchers did not want to kill the prisoners they were experimenting on, for fear of losing valuable research, they decided to flood the area with the pesticide [[chloropicrin]] which they believed to be a harmless tear gas. However, the chloropicrin proved to be fatal to the prisoners in the courtyard, all of whom suffocated.<ref>{{Cite book |last=Harris |first=Sheldon H. |url=https://archive.org/details/factoriesofdeath0000harr/page/71 |title=Factories of death: Japanese biological warfare 1932 - 45 and the American cover-up |date=1999 |publisher=Routledge |isbn=978-0-415-13206-0 |edition=Reprint |location=London |page=71 }}</ref>

The second attempt occurred in the summer of 1945. [[Corporal]] Kikuchi Norimitsu testified that he was told by another unit member that a prisoner "had shown violence and had struck the experimenter with a door handle" and then "jumped out of the cell and ran down the corridor, seized the keys and opened the iron doors and some of the cells. Some of the prisoners managed to jump out but these were only the bold ones. These bold ones were shot."<ref name="trialmaterials" />{{rp|373–374}}

[[Seiichi Morimura]] in his book ''The Devil's Feast'' went into some greater detail regarding the second escape attempt. Two Russian male prisoners were in a cell with handcuffs on, one of them lay flat on the floor pretending to be sick. This got the attention of a staff member who saw it as an unusual condition. That staff member decided to enter the cell. The Russian lying on the floor suddenly sprang up and knocked the guard down. The two Russians opened their handcuffs, took the keys, and opened some other cells while yelling. Some prisoners, including Russian and Chinese, were frantically roaming the corridors and kept yelling and shouting. One Russian shouted to the members of Unit&nbsp;731, demanding to be shot rather than used as an experimental object. This Russian was shot to death.  One staff member, who was an eyewitness at this escape attempt, recalled: "spiritually we were all lost in front of the 'marutas' who had no freedom and no weapons. At that time we understood in our hearts that justice was not on our side."<ref name="auto">{{cite book |last1=Morimura |first1=Seiichi |title=Zu Binghe translation of Ogre's Cave: terrible inside story of the bacteriological warfare unit from Japan's Kwantung Army |date=1984 |publisher=Qunzhong Chubanshe |location=Beijing |pages=108–109}}</ref>

Unfortunately for the prisoners of Unit&nbsp;731, escape was an impossibility. Even if they had managed to escape the quadrangle (itself a heavily fortified building full of staff), they would have had to get over a {{convert|3|m|ft|sp=us|spell=in|adj=mid|-high}} brick wall surrounding the complex, and then across a dry moat filled with [[Electric fence|electrified wire]] running around the perimeter of the complex.<ref>{{cite journal |last1=Harris |first1=Sheldon |title=Japanese Biomedical Experimentation During The World-War-II |journal=Military Medical Ethics |date=2002 |volume=2 |pages=463–506}}</ref>

===Experiments on staff members===
Members of Unit 731 were not immune from being subjects of experiments. Yoshio Tamura, an assistant in the Special Team, recalled that Yoshio Sudō, an employee of the first division at Unit&nbsp;731, became infected with [[bubonic plague]] as a result of its production. The Special Team was then ordered to vivisect Sudō. Tamura recalled:

{{Blockquote|text=Sudō had, a few days previously, been interested in talking about women, but now he was thin as a rake, with many [[buboes|purple spots]] over his body. A large area of scratches on his chest were bleeding. He painfully cried and breathed with difficulty. I sanitised his whole body with disinfectant. Whenever he moved, a rope around his neck tightened. After Sudō's body was carefully checked [by the surgeon], I handed a scalpel to [the surgeon] who, reversely gripping the scalpel, touched Sudō's stomach skin and sliced downward. Sudō shouted "brute!" and died with this last word.|source=''Criminal History of Unit 731 of the Japanese Military'', pp. 118–119 (1991)}}

Additionally, Unit&nbsp;731 Youth Corps member Yoshio Shinozuka testified that his friend junior assistant Mitsuo Hirakawa was vivisected as a result of being accidentally infected with plague.<ref name="autogenerated1">{{cite book |last1=Emanuel |first1=Ezekiel |last2=Grady |first2=Christine |last3=Crouch |first3=Robert |last4=Lie |first4=Reidar |last5=Miller |first5=Franklin |title=The Oxford Textbook of Clinical Research Ethics |date=2011 |publisher=Oxford University Press |location=US}}</ref>

== Personnel and postwar accountability ==

Unit 731 included hundreds of military and civilian personnel who participated in wartime human experimentation, biological weapons development, and chemical warfare. After Japan's surrender, several members were interned at the [[Fushun War Criminals Management Centre]] and the Taiyuan War Criminals Management Centre. Many were later repatriated to Japan, where some became involved in the [[Association of Returnees from China]] and testified about their activities.

=== Key personnel ===
[[File:Shiro-ishii.jpg|thumb|[[Shirō Ishii]], commander of Unit 731|upright=.65]]
[[File:Ryōichi Naitō.png|thumb|Ryōichi Naitō|upright=.65]]
[[File:Yoshimura Hisato.jpg|thumb|[[Yoshimura Hisato]]|upright=.65]]

Prominent members of Unit 731 included:
* [[Lieutenant general|Lieutenant General]] [[Shirō Ishii]] – overall commander
* [[Major general|Major General]] Masaji Kitano – commander (1942–1945)
* [[Lieutenant colonel|Lieutenant Colonel]] Ryōichi Naitō – founder of [[Green Cross (Japan)|Green Cross]]
* [[Prince Tsuneyoshi Takeda]]
* [[Prince Naruhiko Higashikuni]]
* [[Yoshio Shinozuka]] – later gave testimony
* [[Yasuji Kaneko]] – later gave testimony
* [[Shigeru Fujita]]
* [[Ken Yuasa]]
* Civilian employees and students including Shigeo Ozeki, Kioyashi Mineoi, Masateru Saitō, and Yoshio Furuichi<ref name="trialmaterials" />{{rp|243}}

=== Khabarovsk war crimes trials ===
Twelve former members of Unit 731 and associated units were tried by the Soviet Union in 1949 during the [[Khabarovsk war crimes trials]]. The table below lists their ranks, roles, and sentences:

{| class="wikitable"
|-
! scope="col" | Name !! scope="col" | Military position !! scope="col" | Unit position<ref name="trialmaterials" />{{rp|5}} !! scope="col" | Unit !! scope="col" | Sentenced years in labor camp<ref name="trialmaterials" />{{rp|534–535}}
|-
! scope="row" |Kiyoshi Kawashima
| [[Major general]] of the Medical Service<ref name="trialmaterials"/>{{rp|10}}||Chief of General Division, 1939–1941, Head of Production Division, 1941–1945<ref name="shokan">{{cite book |last=Fuller |first=Richard |date=1992 |title=Shōkan: Hirohito's Samurai |publisher=Arms and Armour |isbn=978-1-85409-151-2 |url=https://archive.org/details/shokanhirohitoss00full }}</ref>{{rp|131}} || 731 || 25 (served 7)
|-
! scope="row" | [[Otozō Yamada]]
| [[General officer|General]]|| Direct controller, 1944–1945<ref name="shokan" />{{rp|232}} || 731, 100 || 25 (served 7)
|-
! scope="row" | Ryuji Kajitsuka
| [[Lieutenant general]] of the Medical Service ||Chief of the Medical Administration<ref name="shokan" />{{rp|131}} || 731 || 25 (served 7)
|-
! scope="row" | Takaatsu Takahashi
| Lieutenant general of the Veterinary Service || Chief of the [[Veterinary medicine|Veterinary]] Service || 731 || 25 (died in prison in 1952)
|-
! scope="row" | Tomio Karasawa
| Major of the Medical Service || Chief of a section || 731 || 20 (committed suicide in prison in 1956)
|-
! scope="row" | Toshihide Nishi
| Lieutenant colonel of the Medical Service || Chief of a division || 731 || 18 (served 7)
|-
! scope="row" | Masao Onoue
| [[Major (rank)|Major]] of the Medical Service || Chief of a branch || 731 || 12 (served 7)
|-
! scope="row" | Zensaku Hirazakura
| [[Lieutenant]]|| Officer || 100 || 10 (served 7)
|-
! scope="row" | Kazuo Mitomo
| [[Senior sergeant]]|| Member || 731|| 15 (served 7)
|-
! scope="row" | Norimitsu Kikuchi
| [[Corporal]]|| Probationer medical [[orderly]]|| Branch 643 || 2 (served full term)
|-
! scope="row" | Yuji Kurushima
| [none] || Laboratory orderly || Branch 162 || 3 (served full term)
|-
! scope="row" | [[Shunji Sato]]
| Major general of the Medical Service || Chief of the Medical Service<ref name="shokan" />{{rp|192}} || 731, 1644 || 20 (served 7)
|}

=== Disclosure of membership list ===
In April 2018, the [[National Archives of Japan]] released a near-complete list of 3,607 personnel affiliated with Unit 731 to Katsuo Nishiyama, a professor at [[Shiga University of Medical Science]]. Nishiyama announced his intent to publish the list online to promote further research.<ref>{{cite web |last=McCurry |first=Justin |title=Japan publishes list of members of Unit 731 imperial army branch |url=https://www.theguardian.com/world/2018/apr/17/japan-unit-731-imperial-army-second-world-war |website=The Guardian |date=17 April 2018 |access-date=17 April 2018 |archive-url=https://web.archive.org/web/20180417111333/https://www.theguardian.com/world/2018/apr/17/japan-unit-731-imperial-army-second-world-war |archive-date=17 April 2018 |url-status=live}}</ref>

== Divisions ==
Unit&nbsp;731 was divided into eight divisions:
* Division&nbsp;1: research on [[bubonic plague]], [[cholera]], [[anthrax]], [[typhoid]], and [[tuberculosis]] using live human subjects; for this purpose, a prison was constructed to contain around three to four hundred people
* Division&nbsp;2: research for biological weapons used in the field, in particular the production of devices to spread germs and [[Parasitism|parasites]]
* Division&nbsp;3: production of [[Shell (weapon)|shells]] containing biological agents; stationed in [[Harbin]]
* Division&nbsp;4: bacteria mass-production and storage<ref>{{cite web|title=Unit 731: One of the Most Terrifying Secrets of the 20th Century|url=https://www.mtholyoke.edu/~kann20c/classweb/dw2/page1.html|access-date=November 8, 2015|archive-date=March 8, 2017|archive-url=https://web.archive.org/web/20170308232538/http://www.mtholyoke.edu/~kann20c/classweb/dw2/page1.html}}</ref>
* Division&nbsp;5: training of personnel
* Divisions&nbsp;6–8: equipment, medical, and administrative units

== Facilities ==
{{Main|Epidemic Prevention and Water Purification Department}}
[[File:Main entrance of Harbin's Unit 731 Museum.jpg|thumb|The main entrance of the Unit 731 Museum in Harbin.]]
[[File:Harbin Gedenkplakette Einheit731.JPG|thumb|Information sign at the site today]]

Unit&nbsp;731 had other units underneath it in the [[Chain of Command|chain of command]]; there were several other units under the auspice of [[Epidemic Prevention and Water Purification Department|Japan's biological weapons programs]]. Most or all Units had branch offices, which were also often referred to as "Units." The term Unit&nbsp;731 can refer to the Harbin complex, or it can refer to the organization and its branches, sub-Units and their branches.

The Unit&nbsp;731 complex covered {{convert|6|km2|sqmi|spell=in|sp=us}} and consisted of more than 150&nbsp;buildings. The design of the facilities made them hard to destroy by bombing. The complex contained various factories. It had around 4,500&nbsp;containers to be used to raise [[flea]]s, six [[cauldron]]s to produce various chemicals, and around 1,800&nbsp;containers to produce biological agents. Approximately {{convert|30|kg|lb}} of [[Plague (disease)|bubonic plague bacteria]] could be produced in a few days. Some of Unit&nbsp;731's satellite (branch) facilities are still in use by various Chinese industrial companies. A portion has been preserved and is open to visitors as a [https://unit731.org/harbin-museum/ museum].<ref>{{cite web|title=Harbin museum – Unit 731|url=https://unit731.org/harbin-museum/|access-date=2020-08-10|language=en-US|archive-date=2020-10-23|archive-url=https://web.archive.org/web/20201023024127/https://unit731.org/harbin-museum/|url-status=live}}</ref>

=== Branches ===
Unit&nbsp;731 had branches in [[Linkou County|Linkou]] (Branch&nbsp;162), [[Mudanjiang]], [[Hailin]] (Branch&nbsp;643), [[Sunwu County|Sunwu]] (Branch&nbsp;673) and [[Hailar District|Hailar]] (Branch&nbsp;543).<ref name="trialmaterials" />{{rp|60, 84, 124, 310}}

=== Tokyo ===
A medical school and research facility belonging to Unit&nbsp;731 operated in the [[Shinjuku, Tokyo|Shinjuku]] District of [[Tokyo]] during World War&nbsp;II. In 2006, Toyo Ishii—a nurse who worked at the school during the war—revealed that she had helped bury bodies and pieces of bodies on the school's grounds shortly after [[Surrender of Japan|Japan's surrender]] in 1945. In response, in February&nbsp;2011 the [[Ministry of Health, Labour and Welfare (Japan)|Ministry of Health]] began to excavate the site.<ref>[[Associated Press]], "[https://www.japantimes.co.jp/news/2011/02/22/national/work-starts-at-shinjuku-unit-731-site/ Work starts at Shinjuku Unit 731 site] {{Webarchive|url=https://web.archive.org/web/20181224023705/https://www.japantimes.co.jp/news/2011/02/22/national/work-starts-at-shinjuku-unit-731-site/ |date=2018-12-24 }}", ''[[Japan Times]]'', 22 February 2011, p. 1.</ref>

While Tokyo courts acknowledged in 2002 that Unit&nbsp;731 has been involved in biological warfare research, {{as of|2011|lc=y}} the Japanese government had made no official acknowledgment of the atrocities committed against test subjects and rejected the Chinese government's requests for [[Genetic testing|DNA samples]] to identify human remains (including skulls and bones) found near an army medical school.<ref>{{cite news|newspaper=[[The Economist]]|url=https://www.economist.com/asia/2011/02/24/deafening-silence|title=Deafening silence|date=24 February 2011|page=48|access-date=16 March 2011|archive-date=3 March 2011|archive-url=https://web.archive.org/web/20110303063531/http://www.economist.com/node/18237081?story_id=18237081|url-status=live}}</ref>

== Surrender and immunity ==

=== Destruction of evidence ===
[[File:A photograph of the Unit 731 square building taken during its destruction in 1945.jpg|thumb|The Unit&nbsp;731 square building during its demolition in 1945]]

As the Second World War started to come to an end, all prisoners within the compound were killed to conceal evidence, and there were no documented survivors.<ref>{{cite journal | pmc=4487829 | year=2014 | last1=Brody | first1=H. | last2=Leonard | first2=S. E. | last3=Nie | first3=J. B. | last4=Weindling | first4=P. | title=United States Responses to Japanese Wartime Inhuman Experimentation after World War II: National Security and Wartime Exigency | journal=Cambridge Quarterly of Healthcare Ethics | volume=23 | issue=2 | pages=220–230 | doi=10.1017/S0963180113000753 | pmid=24534743 }}</ref> With the coming of the [[Red Army]] in [[Soviet invasion of Manchuria|August&nbsp;1945]], the unit had to abandon their work in haste. Ministries in Tokyo ordered the destruction of all incriminating materials, including those in [[Pingfang District|Pingfang]]. Potential witnesses, such as the 300 remaining prisoners, were either gassed or fed poison while the 600 Chinese and Manchurian laborers were shot. Ishii ordered every member of the group to disappear and "take the secret to the grave".<ref>{{cite web|url=https://www.umflint.edu/sites/default/files/groups/Research_and_Sponsored_Programs/MOM/b.altheide.pdf|title=Biohazard: Unit 731 and the American Cover-Up|page=5|access-date=2019-05-31|archive-date=2019-07-31|archive-url=https://web.archive.org/web/20190731012542/https://www.umflint.edu/sites/default/files/groups/Research_and_Sponsored_Programs/MOM/b.altheide.pdf}}</ref> Potassium cyanide vials were issued for use in case the remaining personnel were captured. Skeleton crews of Ishii's Japanese troops blew up the compound in the final days of the war to destroy evidence of their activities, but many were sturdy enough to remain somewhat intact.

Former Unit 731 member Hideo Shimizu stated that during the [[Soviet invasion of Manchuria]] he was instructed to eliminate evidence by burning the victims in the courtyard, collecting the leftover bones from the area, and then destroying the remains with explosives.<ref name="auto3"/> While boarding a departing train, he was provided with a cyanide compound and instructed to commit suicide instead of being captured.<ref name="auto3"/>

===American grant of immunity===

Among the individuals in Japan after its 1945 surrender was Lieutenant Colonel [[Murray Sanders]], who arrived in [[Yokohama]] via the American ship ''Sturgess'' in September&nbsp;1945. Sanders was a highly regarded [[microbiologist]] and a member of America's military center for biological weapons. Sanders' duty was to investigate Japanese biological warfare activity. At the time of his arrival in Japan, he had no knowledge of what Unit&nbsp;731 was.<ref name="gold-testimony">{{cite book|title=Unit 731 Testimony|last1=Gold|first1=Hal|date=2011|publisher=Tuttle Pub.|isbn=978-1-4629-0082-4|edition=1st|location=New York|pages=157–158}}</ref> Until Sanders finally threatened the Japanese with bringing the Soviets into the picture, little information about biological warfare was being shared with the Americans. The Japanese wanted to avoid prosecution under the [[Law of the Soviet Union|Soviet legal system]], so, the morning after he made his threat, Sanders received a manuscript describing Japan's involvement in biological warfare.

Sanders took this information to General [[Douglas MacArthur]], who was the [[Supreme Commander for the Allied Powers|Supreme Commander of the Allied Powers]] and responsible for rebuilding Japan during the Allied occupations. MacArthur struck a deal with Japanese [[informant]]s:<ref>{{cite book |last1=Gold |first1=Hal |title=Unit 731 Testimony |date=2011 |publisher=[[Tuttle Publishing]] |location=New York |isbn=978-1-4629-0082-4 |page=96&ndash;97 |edition=1st}}</ref> he secretly granted [[Immunity from prosecution|immunity]] to the physicians of Unit&nbsp;731, including their leader, in exchange for providing exclusive American access to their research on biological warfare and data from human experimentation.<ref name="Gold 2003 p109" /> American occupation authorities monitored the activities of former unit members, including reading and censoring their mail.<ref>[[Kyodo News]], "[http://search.japantimes.co.jp/cgi-bin/nn20100210f3.html Occupation censored Unit 731 ex-members' mail: secret paper] {{Webarchive|url=https://web.archive.org/web/20100805092306/http://search.japantimes.co.jp/cgi-bin/nn20100210f3.html |date=2010-08-05 }}", ''[[Japan Times]]'', February 10, 2010, p. 3.</ref> The Americans believed that the research data was valuable and did not want other nations, particularly the Soviet Union, to acquire data on biological weapons.<ref name="2002-02-01 BBC News">{{cite news |last1=McNaught |first1=Anita |author-link1=Anita McNaught |date=2002-02-01 |title=Unit 731: Japan's biological force |url=https://news.bbc.co.uk/2/hi/programmes/correspondent/1796044.stm |url-status=live |editor1-last=Murch |editor1-first=Fiona |editor2-last=Durrani |editor2-first=Farah |language=en |publisher=[[BBC News]] |archive-url=https://web.archive.org/web/20171229164025/http://news.bbc.co.uk/2/hi/programmes/correspondent/1796044.stm |archive-date=2017-12-29 |access-date=2024-04-18 |quote=Unit 731 was a special division of the Japanese Army, a scientific and military elite. It had a huge budget specially authorised by the Emperor, to develop weapons of mass destruction that would win the war for Japan. America and Germany had their nuclear arms race. Japan put its faith in germs. Anita McNaught reports.}}</ref>

The [[Tokyo War Crimes Tribunal]] heard only one reference to Japanese experiments with "poisonous serums" on Chinese civilians. This took place in August&nbsp;1946 and was instigated by Joseph R Massey, assistant to the Chinese prosecutor. The Japanese defense counsel argued that the claim was vague and uncorroborated and it was dismissed by the tribunal president, Sir [[William Webb (judge)|William Webb]], for lack of evidence. The subject was not pursued further by Massey, who was probably unaware of Unit&nbsp;731's activities. His reference to it at the trial is believed to have been accidental. Later in 1981, one of the last surviving members of the Tokyo Tribunal, Judge Röling, had expressed bitterness in not being made aware of the suppression of evidence of Unit 731 and wrote, "It is a bitter experience for me to be informed now that centrally ordered Japanese war criminality of the most disgusting kind was kept secret from the court by the U.S. government."<ref>{{Cite web |title=The United States and the Japanese Mengele: Payoffs and Amnesty for Unit 731 |url=https://apjjf.org/-Christopher-Reed/2177/article.html |access-date=2023-01-03 |website=The Asia-Pacific Journal: Japan Focus|date=14 August 2006 }}</ref>

American investigations into Japanese war crimes ceased when Japanese scientists began disclosing information on biological warfare. Despite the establishment of their own research program, American scientists faced a significant gap in essential knowledge regarding biological warfare. The potential value to the Americans of Japanese-provided data, encompassing human research subjects, delivery system theories, and successful field trials, was immense. However, historian Sheldon H. Harris concluded that the Japanese data failed to meet American standards, suggesting instead that the findings from the unit were of minor importance at best. Harris characterized the research results from the Japanese camp as disappointing, concurring with the assessment of Murray Sanders, who characterized the experiments as "crude" and "ineffective".<ref name="schulich.uwo.ca"/>

While [[Nuremberg trials|German physicians were brought to trial]] and had their crimes publicized, the U.S. concealed information about Japanese biological warfare experiments and secured immunity for the perpetrators.  Critics have argued that racism led to the double standard in the American postwar responses to the experiments conducted on different nationalities.{{Additional citation needed|date=March 2025}} Whereas the perpetrators of Unit 731 were exempt from prosecution, the U.S. held a tribunal in [[Yokohama]] in 1948 that indicted nine Japanese physician professors and medical students for conducting vivisection upon captured American pilots; two professors were sentenced to death and others to 15–20 years' imprisonment.<ref name="experimentation220">{{cite journal |pmc=4487829 |year=2014 |last1=Brody |first1=H. |last2=Leonard |first2=S. E. |last3=Nie |first3=J. B. |last4=Weindling |first4=P. |title=United States Responses to Japanese Wartime Inhuman Experimentation after World War II: National Security and Wartime Exigency |journal=[[Cambridge Quarterly of Healthcare Ethics]] |volume=23 |issue=2 |pages=220–230 |doi=10.1017/S0963180113000753 |pmid=24534743}}</ref>

=== Separate Soviet trials ===
Although publicly silent on the issue at the Tokyo Trials, the Soviet Union pursued the case and prosecuted 12 top military leaders and scientists from Unit&nbsp;731 and its affiliated biological-war prisons [[Unit 1644|Unit&nbsp;1644]] in [[Nanjing]] and [[Unit 100|Unit&nbsp;100]] in [[Changchun]] in the [[Khabarovsk war crimes trials]]. Among those accused of [[war crime]]s, including germ warfare, was General [[Otozō Yamada]], [[commander-in-chief]] of the million-man [[Kwantung Army]] occupying Manchuria.

The trial of the Japanese perpetrators was held in [[Khabarovsk]] in December&nbsp;1949; a lengthy partial transcript of trial proceedings was published in different languages the following year by the [[Moscow]] foreign languages press, including an English-language edition.<ref>''Materials on the Trial of Former Servicemen of the Japanese Army Charged with Manufacturing and Employing Bacteriological Weapons'' (Moscow: Foreign Languages Publishing House, 1950). (French language: Documents relatifs au procès des anciens Militaires de l'Armée Japonaise accusés d'avoir préparé et employé l'Arme Bactériologique / Japanese language: 細菌戦用兵器ノ準備及ビ使用ノ廉デ起訴サレタ元日本軍軍人ノ事件ニ関スル公判書類 / Chinese language: 前日本陸軍軍人因準備和使用細菌武器被控案審判材料)</ref> The lead prosecuting attorney at the Khabarovsk trial was [[Lev Smirnov]], who had been one of the top Soviet prosecutors at the [[Nuremberg Trials]]. The Japanese doctors and army commanders who had perpetrated the Unit&nbsp;731 experiments received sentences from the Khabarovsk court ranging from 2 to 25&nbsp;years in a [[Siberia]]n [[Gulag|labor camp]]. The United States refused to acknowledge the trials, branding them communist propaganda.<ref>Takashi Tsuchiya. "The Imperial Japanese Experiments in China". ''The Oxford Textbook of Clinical Research Ethics'', pp, 35, 42. Oxford University Press, 2011.</ref> The sentences doled out to the Japanese perpetrators were unusually lenient by Soviet standards, and all of the defendants returned to Japan by 1956.<ref name=":1" />

In addition to the accusations of propaganda, the US also asserted that the trials served as a distraction from the Soviet treatment of several hundred thousand Japanese prisoners of war; meanwhile, the USSR asserted that the US had given the Japanese diplomatic leniency in exchange for information about their human experimentation. However, it is likely that former Unit 731 members had also passed information about their biological experimentation to the Soviet government in exchange for judicial leniency.<ref name=":1">{{Cite book |last=Harris |first=Sheldon H. |url=https://archive.org/details/factoriesofdeath0000harr/page/229 |title=Factories of death: Japanese biological warfare 1932 - 45 and the American cover-up |date=1999 |publisher=Routledge |isbn=978-0-415-13206-0 |edition=Reprint |location=London |pages=229–230}}</ref> The Soviet Union built a [[Sverdlovsk anthrax leak|biological weapons facility in Sverdlovsk]] using documentation captured from Unit&nbsp;731 in Manchuria.<ref name="Alibek">[[Ken Alibek]] and S. Handelman. ''[[Biohazard (book)|Biohazard: The Chilling True Story of the Largest Covert Biological Weapons Program in the World – Told from Inside by the Man Who Ran it]]''. 1999. Delta (2000) {{ISBN|0385334966}}.</ref>

=== Official silence during the American occupation of Japan ===
As above, during the United States occupation of Japan, the members of Unit&nbsp;731 and the members of other experimental units were allowed to go free. On 6&nbsp;May 1947, [[Douglas MacArthur]], the [[Supreme Commander of the Allied Forces]], wrote to [[Washington, D.C.|Washington]] in order to inform it that "additional data, possibly some statements from Ishii, can probably be obtained by informing Japanese involved that information will be retained in [[Intelligence analysis|intelligence channels]] and will not be employed as war crimes evidence".<ref name="Gold 2003 p109" />

According to an investigation by [[The Observer]], after the end of the war, under the pretense of vaccine development, former members of Unit 731 conducted human experiments on Japanese prisoners, babies and mental patients. The Observer article claimed that funding came from the US government, but did not provide any evidence for this claim. <ref>{{cite news |last=McGILL |first=PETER |date=Aug 21, 1983 |title=Postwar Japan: "US Backed Japan's Germ Tests on Mentally Sick" |page=6 |location=London, Greater London, England |url=https://theguardian.newspapers.com/article/122763034/postwar-japan-us-backed-japans-germ/ |work=The Observer}}</ref> One graduate of [[Unit 1644]], Masami Kitaoka, continued to perform experiments on unwilling Japanese subjects from 1947 to 1956. He performed his experiments while he was working for Japan's National Institute of Health Sciences. He infected prisoners with [[rickettsia]] and infected mentally-ill patients with [[typhus]].<ref>日本弁護士連合会『人権白書昭和43年版』日本弁護士連合会、1968年、pp. 126–134</ref> As the chief of the unit, [[Shirō Ishii]] was granted immunity from prosecution for war crimes by the American occupation authorities, because he had provided human experimentation research materials to them. From 1948 to 1958, less than five percent of the documents were transferred onto microfilm and stored in the [[National Archives and Records Administration|US National Archives]] before they were shipped back to Japan.<ref>Human Lab Rats: Japanese Atrocities, the Last Secret of World War II (Penthouse, May 2000)</ref>

=== Post-occupation Japanese media coverage and debate ===
Japanese discussions of Unit 731's activity began in the 1950s, after the end of the [[American occupation of Japan]]. In 1952, an infant girl at [[Nagoya City]] [[Children's hospital|Pediatric Hospital]] died after being infected with ''[[Escherichia coli|E. coli]]'' bacteria; the incident was publicly tied to former Unit 731 scientists.<ref>日本弁護士連合会『人権白書昭和43年版』日本弁護士連合会、1968年、pp. 134–136；高杉晋吾『七三一部隊細菌戦の医師を追え』徳間書店、1982年、pp. 94–111; [http://www.nichibenren.or.jp/activity/document/civil_liberties/year/1955/1955_4.html 保護施設収容者に対する人権擁護に関する件（決議）] {{Webarchive|url=https://web.archive.org/web/20160127043917/http://www.nichibenren.or.jp/activity/document/civil_liberties/year/1955/1955_4.html |date=2016-01-27 }}</ref> Later in that decade, journalists suspected that the murders attributed by the government to [[Sadamichi Hirasawa]] were actually carried out by members of Unit&nbsp;731. In 1957, Japanese author [[Shūsaku Endō]] published the book ''[[The Sea and Poison]]'' about human experimentation in [[Fukuoka]], which is thought to have been based on a real incident.

In 1950, former members of Unit 731 including Masaji Kitano founded the [[blood bank]] and pharmaceutical company [[Green Cross (Japanese company)|Green Cross]], for which Murray Sanders also served as a consultant. The company became the target of a [[HIV-tainted-blood scandal|scandal]] in the 1980s after up to 3,000 Japanese contracted [[HIV]] through the distribution and use of its blood products, which the [[Pharmaceuticals and Medical Devices Agency]] had deemed unsafe.<ref>{{Cite web |date=2021-05-26 |title=JPRI Working Paper No. 23 |url=http://www.jpri.org/publications/workingpapers/wp23.html |access-date=2024-03-26 |archive-url=https://web.archive.org/web/20210526145652/http://www.jpri.org/publications/workingpapers/wp23.html |archive-date=26 May 2021 }}</ref><ref>{{Cite web | url=https://search.japantimes.co.jp/cgi-bin/fl20091101x4.html | title=Ministry insider speaks out | website=search.japantimes.co.jp | first=Tomoko | last=Otake | date=2009-11-01}}</ref>

The author [[Seiichi Morimura]] published ''The Devil's Gluttony'' (悪魔の飽食) in 1981, followed by ''The Devil's Gluttony: A Sequel'' in 1983. These books purported to reveal the "true" operations of Unit&nbsp;731, but falsely attributed unrelated photos to the Unit, which raised questions about their accuracy.<ref>{{cite book |title=Textbook controversy and the production of public truth: Japanese education, nationalism, and Saburo Ienaga's court challenges |last=Nozaki |first=Yoshiko |year=2000 |publisher=University of Wisconsin–Madison |pages=300, 381}}</ref><ref>{{cite book|author=Keiichi Tsuneishi|title=『七三一部隊 生物兵器犯罪の真実』 講談社現代新書 |year=1995|isbn=4-06-149265-9|page=171|publisher=講談社 }}</ref> Also in 1981, the first direct testimony of human [[vivisection]] in China was given by [[Ken Yuasa]]. Since then, much more in depth testimony has been given in Japan. The 2001 documentary ''[[Japanese Devils]]'' largely consists of interviews with fourteen Unit&nbsp;731 staff members taken prisoner by China and later released.<ref>田辺敏雄 『検証 旧日本軍の「悪行」—歪められた歴史像を見直す』 自由社 {{ISBN|4915237362}}</ref> [[Takahito, Prince Mikasa|Prince Mikasa]], who was the younger brother of Hirohito, toured the Unit 731 headquarters in China, and wrote in his memoir that he watched films showing how Chinese prisoners were "made to march on the plains of Manchuria for poison gas experiments on humans."<ref name="Kristof"/> [[Hideki Tojo]], who later became [[Prime Minister of Japan|Prime Minister]] in 1941, was also shown films of the experiments, which he described as "unpleasant".<ref>{{Cite journal |last=Vanderbrook |first=Alan |date=2013 |title=Imperial Japan's Human Experiments Before And During World War Two |url=https://stars.library.ucf.edu/cgi/viewcontent.cgi?article=3588&context=etd |journal=Electronic Theses and Dissertations, 2004-2019 |via=STARS}}</ref>

=== Significance in postwar research on bio-warfare and medicine ===
Despite conducting scientific experiments, Unit 731 faced scrutiny regarding the usefulness of the data produced from these experiments.<ref name="schulich.uwo.ca"/> Japanese biological warfare [[Military operation|operation]]s were by far the largest during WWII, and "possibly with more people and resources than the BW producing nations of France'','' Hungary'','' Italy'','' Poland'','' and the Soviet Union combined, between the world wars.<ref>A Short History of Biological Warfare (PDF) p. 12</ref> Despite the apparent success, Unit 731 lacked adequate scientific and engineering foundations to further maximize its effectiveness.<ref>A Short History of Biological Warfare (PDF) p. 27</ref><ref>{{cite web|url=https://wmdcenter.ndu.edu/Portals/68/Documents/occasional/cswmd/CSWMD_OccasionalPaper-12.pdf?ver=2017-08-07-142315-127|title=A Short History of Biological Warfare|page=15|access-date=2019-05-31|archive-date=2019-05-31|archive-url=https://web.archive.org/web/20190531063447/https://wmdcenter.ndu.edu/Portals/68/Documents/occasional/cswmd/CSWMD_OccasionalPaper-12.pdf%3Fver%3D2017-08-07-142315-127|url-status=live}}</ref> Harris concluded that US scientists generally wanted to acquire it due to the concept of [[forbidden fruit]], believing that lawful and ethical prohibitions could affect the outcomes of their research.<ref>{{Cite book |last=Harris |first=Sheldon H. |url=https://archive.org/details/factoriesofdeath0000harr/page/222 |title=Factories of death: Japanese biological warfare 1932 - 45 and the American cover-up |date=1999 |publisher=Routledge |isbn=978-0-415-13206-0 |edition=Reprint |location=London |page=222}}</ref>

Historian [[Till Winfried Bärnighausen]] criticized the overall lack of scientific rigor in many of Unit 731's experiments, but he noted some exceptions. He pointed to the mustard gas, freezing, and tuberculosis experiments as having a reliable and valid data collection process, suggesting they were conducted with greater rigor.<ref name="schulich.uwo.ca"/>

In 1969, Ikeda Naeo, a physician associated with Unit 731, published his own research on [[Viral hemorrhagic fever|epidemic hemorrhagic fever]] (EHF). His paper documented experiments conducted at a military hospital on the China-Soviet border in January 1942. These experiments, involving infections on humans, confirmed the transmission of EHF by lice and fleas to local populations, resulting in deaths among those infected. Despite the explicit admission of conducting experiments on humans with fatal pathogenic inoculations, Ikeda's report passed [[peer review]] and was published in a Japanese scholarly journal. The acceptance of this research by Ikeda underscored the widespread acknowledgment within the Japanese medical community of the human experiments conducted at Unit 731.<ref name="Dark medicine: rationalizing unethi">{{cite book |last1=LaFleur| url=https://books.google.com/books?id=gGQYOvo9-AsC&q=Yoshimura+ |first1=William |last2=Böhme |first2=Gernot |last3=Shimazono |first3=Susumu |title=Dark medicine: rationalizing unethical medical research |date=2007 |publisher=Indiana University Press|page=79 |location=US| isbn=978-0-253-22041-7 }}</ref>

During the war, Yoshimura Hisato conducted research at Unit 731 in China focusing on low-temperature physiology, particularly studying the mechanisms involved in frostbite. Following the war, he established the Japanese Society of Biometeorology. His research in China marked the inception of his exploration into the relationship between physiology and environmental stress.<ref name="Dark medicine: rationalizing unethi"/>

Most researchers at Unit 731 did not engage in a concerted effort to conceal the experiments they participated in. While they refrained from publicly acknowledging their crimes, they did share various details within their medical circles. Consequently, especially regarding research on EHF and frostbite, it has been relatively straightforward to ascertain who conducted which type of human experiments. Given that nearly all members of the Japanese medical community were aware of the human experiments conducted at Unit 731, researchers from the Unit were able to later publish their work in medical papers. Even after the war, reports were disseminated unmistakably detailing the results of experiments on humans, and accounts of the Unit were documented in medical journals. This indicates widespread awareness within the Japanese medical community regarding the experiments carried out at Unit 731.<ref name="Dark medicine: rationalizing unethi"/>

During the [[COVID-19 pandemic]], some scientists called for experimental data from Unit 731 to be publicly released to the international medical community because the data available on human-pathogen interactions could have helped epidemiologists with pandemic control.<ref name=":3">{{Cite journal |last1=Su |first1=Zhaohui |last2=McDonnell |first2=Dean |last3=Cheshmehzangi |first3=Ali |last4=Abbas |first4=Jaffar |last5=Li |first5=Xiaoshan |last6=Cai |first6=Yuyang |date=2021 |title=The promise and perils of Unit 731 data to advance COVID-19 research |journal=BMJ Global Health |volume=6 |issue=5 |article-number=e004772 |doi=10.1136/bmjgh-2020-004772 |pmid=34016575 |pmc=8141376 }}</ref> The information has been withheld by both the US and Japanese government.

=== Official government response in Japan ===
{{See also|List of war apology statements issued by Japan}}
In 1983, the [[Japanese Ministry of Education]] asked Japanese historian [[Saburō Ienaga]] to remove a reference from one of his textbooks that stated Unit 731 conducted experiments on thousands of Chinese. The ministry alleged that no academic research supported the claim. In 1984, Japanese historian Tsuneishi Keiichi translated and published over 4,000 pages of U.S. documents on Japanese biological warfare. The ministry backed down after new studies were published in Japan and important evidence surfaced in the United States.<ref>{{cite book|title=Researching Japanese War Crimes|publisher=National Archives and Records Administration for the Nazi Warcrimes and Japanese Imperial Government Records Interagency Working Group|date=2006|page=35|last=Drea|first=Edward|url=https://www.archives.gov/files/iwg/japanese-war-crimes/introductory-essays.pdf}}</ref>

Japanese history textbooks usually contain references to Unit&nbsp;731, but the textbooks do not provide specific details about the activities conducted at the facility.<ref>Yoshiko Nozaki and Mark Selden, ''The Asia-Pacific Journal: Japan Focus'' [http://www.japanfocus.org/-Mark-Selden/3173 "Japanese Textbook Controversies, Nationalism, and Historical Memory: Intra- and Inter-national Conflicts"] {{Webarchive|url=https://web.archive.org/web/20120724222632/http://japanfocus.org/-mark-selden/3173 |date=2012-07-24 }}</ref><ref>{{cite web |author=Kathleen Woods Masalski |url=http://spice.stanford.edu/docs/134 |title=Examining the Japanese History Textbook Controversies |publisher=Stanford Program on International and Cross-Cultural Education |date=November 2001 |access-date=2012-07-30 |archive-date=2018-01-14 |archive-url=https://web.archive.org/web/20180114164704/http://spice.fsi.stanford.edu/ |url-status=live }}</ref> Saburō Ienaga's ''New History of Japan'' included a detailed description, based on officers' testimony. The Ministry for Education attempted to remove this passage from his textbook before it was taught in public schools, on the basis that the testimony was insufficient. The [[Supreme Court of Japan]] ruled in 1997 that the testimony was indeed sufficient and that requiring it to be removed was an illegal violation of [[freedom of speech]].<ref>''[[Asahi Shimbun]]'' editorial, August 30, 1997</ref>

In 1997, [[international lawyer]] Kōnen Tsuchiya filed a [[class action]] suit against the Japanese government, demanding [[Reparations (transitional justice)|reparations]] for the actions of Unit&nbsp;731, using evidence filed by Professor Makoto Ueda of [[Rikkyo University]]. All levels of the Japanese court system found the suit baseless. No findings of fact were made about the existence of human experimentation. In August&nbsp;2002, the [[Tokyo District Court|Tokyo district court]] ruled for the first time that Japan had engaged in biological warfare. Presiding judge Koji Iwata ruled that Unit&nbsp;731, on the orders of the Imperial Japanese Army headquarters, used bacteriological weapons on Chinese civilians between 1940 and 1942, spreading diseases, including [[Plague (disease)|plague]] and [[Typhoid fever|typhoid]], in the cities of [[Quzhou]], [[Ningbo]], and [[Changde]]. He rejected victims' compensation claims on the grounds that they had already been settled by international peace treaties.<ref>{{cite web|url=https://www.theguardian.com/world/2002/aug/28/artsandhumanities.japan|title=Japan guilty of germ warfare against thousands of Chinese|last=Watts|first=Jonathan|date=2002-08-28|website=The Guardian|access-date=2018-10-02|archive-date=2018-09-11|archive-url=https://web.archive.org/web/20180911152228/https://www.theguardian.com/world/2002/aug/28/artsandhumanities.japan|url-status=live}}</ref>

In October 2003, a member of [[House of Representatives (Japan)|Japan's House of Representatives]] filed an inquiry. [[Junichiro Koizumi|Prime Minister Junichiro Koizumi]] responded that the Japanese government did not then possess any records related to Unit&nbsp;731, but recognized the gravity of the matter and would publicize any records located in the future.<ref>「[http://www.shugiin.go.jp/itdb_shitsumon.nsf/html/shitsumon/b157024.htm 衆議院議員川田悦子君提出七三一部隊等の旧帝国陸軍防疫給水部に関する質問に対する答弁書] {{Webarchive|url=https://web.archive.org/web/20130120204524/http://www.shugiin.go.jp/itdb_shitsumon.nsf/html/shitsumon/b157024.htm |date=2013-01-20 }}」 October 10, 2003.</ref> In April&nbsp;2018, the [[National Archives of Japan]] released the names of 3,607&nbsp;members of Unit&nbsp;731, in response to a request by Professor Katsuo Nishiyama of the [[Shiga University of Medical Science]].<ref>{{cite news |newspaper=[[The Japan Times]] |url=https://www.japantimes.co.jp/news/2018/04/16/national/history/names-3607-members-imperial-japanese-armys-unit-731-released/ |date=April 16, 2018 |title=Names of 3,607 members of Imperial Japanese Army's notorious Unit 731 released by national archives |access-date=April 17, 2018 |archive-date=April 18, 2018 |archive-url=https://web.archive.org/web/20180418105008/https://www.japantimes.co.jp/news/2018/04/16/national/history/names-3607-members-imperial-japanese-armys-unit-731-released/ |url-status=live }}</ref><ref>{{cite web|url=http://www.theguardian.com/world/2018/apr/17/japan-unit-731-imperial-army-second-world-war|title=Unit 731: Japan discloses details of notorious chemical warfare division|date=April 17, 2018|website=the Guardian|access-date=September 24, 2021|archive-date=September 5, 2021|archive-url=https://web.archive.org/web/20210905104550/https://www.theguardian.com/world/2018/apr/17/japan-unit-731-imperial-army-second-world-war|url-status=live}}</ref>

=== Abroad ===
After World War&nbsp;II, the [[Office of Special Investigations (United States Department of Justice)|Office of Special Investigations]] created a watchlist of suspected [[Axis collaborators]] and persecutors banned from entering the United States. While over 60,000&nbsp;names were added to the watchlist, fewer than 100 Japanese participants were identified. In a 1998 correspondence letter between the [[Department of Justice (United States)|DOJ]] and Rabbi Abraham Cooper, Eli Rosenbaum, director of OSI, stated that this was due to two factors:

# While most documents captured by the US in Europe were [[Microfilmer|microfilmed]] before being returned to their respective governments, the [[United States Department of Defense|Department of Defense]] decided not to microfilm its vast collection of documents before returning them to the Japanese government.
# The Japanese government has also failed to grant the OSI meaningful access to these and related records after the war, while European countries, on the other hand, were largely cooperative.<ref>{{cite web |url=https://assets.documentcloud.org/documents/3720697/DOJ-Copy-Cooper-1998-Correspondence.pdf |title=Fax to Rabbi Abraham Cooper |access-date=2017-10-27 |archive-date=2019-05-28 |archive-url=https://web.archive.org/web/20190528225700/https://assets.documentcloud.org/documents/3720697/DOJ-Copy-Cooper-1998-Correspondence.pdf |url-status=live }}</ref> The cumulative effect was that information needed to identify these individuals became, in effect, impossible to recover.

== In popular culture ==

=== Print media ===
* ''[[The Narrow Road to the Deep North (novel)|The Narrow Road to the Deep North]]'' (2014), novel by [[Richard Flanagan]]. A [[Booker Prize]]-winning story featuring a doctor involved in atrocities resembling those of Unit&nbsp;731.
* ''Wood Sea'' ({{langx|pl|Leśne morze}}) (1984), novel by [[Igor Newerly]]. The first non-Asian novel to reference Unit&nbsp;731 atrocities.
* ''The Man Who Ended History: A Documentary'' (2011), novella by [[Ken Liu]]. A speculative story about time-travel investigations into atrocities like those committed by Unit&nbsp;731.
* ''[[Tricky Twenty-Two]]'' (2015), novel by [[Janet Evanovich]]. Features a villainous biology professor attempting to recreate Unit&nbsp;731's plague dispersals.
* ''[[The Solomon Curse]]'' (2015), novel by [[Clive Cussler]] and [[Russell Blake (author)|Russell Blake]]. Includes a subplot about secret human experimentation linked to Unit&nbsp;731.
* ''The Grimnoire Chronicles'' (2011–2014), novel series by [[Larry Correia]]. Depicts magical experiments conducted by the Japanese Imperium, paralleling Unit&nbsp;731's work.
* ''Setting Sun'' (1999), short story in ''[[Hellblazer]]'' #142 by [[Warren Ellis]]. Features a character who was a wartime doctor in Unit&nbsp;731.
* ''[[My Hero Academia]]'' (2010–), manga by [[Kōhei Horikoshi]]. A character originally named "Shiga Maruta" sparked backlash for referencing Unit&nbsp;731's human test subjects.<ref name=scmp>{{cite web | url=https://www.scmp.com/abacus/culture/article/3048990/hit-manga-my-hero-academia-removed-china-over-war-crimes-reference | title=Hit manga My Hero Academia removed in China over war crimes reference | date=February 4, 2020 | author=Ye, Josh | work=[[South China Morning Post]] | access-date=November 11, 2020 | archive-date=November 19, 2020 | archive-url=https://web.archive.org/web/20201119104052/https://www.scmp.com/abacus/culture/article/3048990/hit-manga-my-hero-academia-removed-china-over-war-crimes-reference | url-status=live }}</ref> The name was later changed.<ref>{{cite web |url=https://www.animenewsnetwork.com/interest/2020-02-10/my-hero-academia-manga-updated-with-villain-new-name/.156305 |title=My Hero Academia Manga Updated With Villain's New Name |author=Loveridge, Lynzee |date=10 February 2020 |website=[[Anime News Network]] |access-date=11 November 2020 |archive-date=20 June 2020 |archive-url=https://web.archive.org/web/20200620042726/https://www.animenewsnetwork.com/interest/2020-02-10/my-hero-academia-manga-updated-with-villain-new-name/.156305 |url-status=live }}</ref>
* ''Crisis in the Ashes'' (1999), novel by [[William W. Johnstone]]. Features the grandson of a Unit&nbsp;731 scientist using plague as a weapon.
* ''The Collector – Unit 731'' (2021), comic miniseries by [[Dark Horse Comics]], written by Rod Monteiro and illustrated by Will Conrad. Follows a POW captured and experimented on by Unit 731.
* ''Inheritors'' (2020), short story collection by [[Asako Serizawa]]. Includes "Train to Harbin," about a Japanese doctor reflecting on his wartime crimes.<ref>{{cite web |last=Davison Aviles |first=Marcela |date=14 July 2020 |title='Inheritors' Maps A Complicated Family Tree Through The Centuries |work=[[NPR]] |url=https://www.npr.org/2020/07/14/890571662/inheritors-maps-a-complicated-family-tree-through-the-centuries |access-date=3 January 2025}}</ref>
* ''The English Führer'' (2023), novel by [[Rory Clements]]. Involves biological weapons developed by Unit&nbsp;731.<ref>{{cite web |title=The English Führer by Rory Clements – Historia Magazine |url=https://www.historiamag.com/the-english-fuhrer-by-rory-clements/ |access-date=5 February 2023 |website=Historia Magazine}}</ref>
* ''The Ninth Artifact: The Artifact Series #9'' (2025), novel by David Collins. The chapter entitled "The Spiders Return" mentions "the Japanese vivisection experimentation on prisoners in World War II. Those were stains on the glorious history."

=== Film ===
* ''[[The Sea and Poison (film)|The Sea and Poison]]'' (1986), Japanese film by [[Kei Kumai]]. Dramatizes human experiments modeled on those of Unit&nbsp;731.
* ''[[Men Behind the Sun]]'' (1988), Hong Kong film by [[Tun Fei Mou]]. Graphic dramatization of Unit&nbsp;731's activities.
* ''Unit 731: Laboratory of the Devil'' (1992), Hong Kong film by [[Godfrey Ho]]. Depicts atrocities committed at Unit&nbsp;731.
* ''Men Behind the Sun 3: A Narrow Escape'' (1994),  Hong Kong film by [[Godfrey Ho]]. Presents Unit 731 destroying all evidence before escaping from China. 
* ''731: Two Versions of Hell'' (2007), documentary by [[James T. Hong]]. Presents Chinese and Japanese perspectives on Unit&nbsp;731.<ref>{{cite web |url=https://video.alexanderstreet.com/watch/731-two-versions-of-hell |title=731: Two Versions of Hell |website=Alexander Street |access-date=24 September 2021 |archive-date=26 September 2021 |archive-url=https://web.archive.org/web/20210926025608/https://alexanderstreet.com/ |url-status=live}}</ref>
* ''[[Philosophy of a Knife]]'' (2008), Russian experimental film by Andrey Iskanov. Focuses on the horrors of Unit&nbsp;731.
* ''[[Dead Mine]]'' (2012), Indonesian film by Steven Sheil. Features a fictional offshoot of Unit&nbsp;731's research.
* ''[[Dongju: The Portrait of a Poet]]'' (2016), South Korean film by [[Lee Joon-ik|Lee Jun-ik]]. Depicts Korean poet [[Yun Dong-ju]] who died under suspicious conditions linked to experimentation.
* ''[[Wife of a Spy]]'' (2020), Japanese film by [[Kiyoshi Kurosawa]]. Involves secret footage exposing Unit&nbsp;731's work; won the [[Silver Lion for Best Direction]] at [[Venice Film Festival|Venice]].
* ''[[Evil Unbound]]'' (2025), Chinese film by Linshan Zhao. Dramatization of Unit&nbsp;731's wartime activities.
* ''[[Site (film)|Site]]'' (2025), United States film by Jason Eric Perlman. Science fiction about entangled timelines and lives, particularly a family imprisoned by Unit 731.

=== Music ===
* "The Breeding House" (1994), song by [[Bruce Dickinson]]. Explores unethical experimentation themes.
* "Unit 731" (2009), song by [[Slayer]]. References atrocities committed by Unit&nbsp;731.
* "And You Will Beg for Our Secrets" (2016), song by [[Anaal Nathrakh]]. Inspired by wartime human experimentation.
* "The New Eternity" (2018), song by [[Silent Planet]]. Explores dehumanization and historical atrocities.
* "Maruta" (2009), song by South Korean metal band Sad Legend. References the code name for Unit&nbsp;731 victims.
* "Unit 731" (2021), track by German dubstep producer KROWW. Named after the infamous unit.
* [[Maruta (band)|Maruta]], American grindcore band. Named after the term "maruta" used for test subjects in Unit&nbsp;731.

=== Television ===
* ''Unit 731 – Did the Emperor Know?'' (1985), documentary by [[Television South]]. Investigates Imperial Japan's knowledge of Unit&nbsp;731.<ref>{{cite web |url=http://collections-search.bfi.org.uk/web/Details/ChoiceFilmWorks/150299115 |title=Unit 731 – Did the Emperor Know? |publisher=[[BFI]] |access-date=1 August 2017 |archive-date=1 August 2017 |archive-url=https://web.archive.org/web/20170801233508/http://collections-search.bfi.org.uk/web/Details/ChoiceFilmWorks/150299115 |url-status=live}}</ref>
* "731" (1995), episode of ''[[The X-Files]]''. Depicts continuation of Unit&nbsp;731's experiments under a covert U.S. program.
* "Let It Burn" (2007), episode of ''[[ReGenesis]]''. Connects anthrax and glanders outbreaks to Unit&nbsp;731's wartime work.
* "The 40th Floor" (2011), episode of ''[[Warehouse 13]]''. Features a cursed medal linked to Unit&nbsp;731.
* ''[[Concrete Revolutio]]'' (2015), anime series. Features fictional superhuman experiments paralleling Unit&nbsp;731.
* ''731'' ({{lang-zh|s=七三一}}) (2015), five-part [[China Central Television|CCTV]] documentary. Chronicles Unit&nbsp;731's crimes and postwar legacy.
* ''The Truth of Unit 731: Elite Medical Students and Human Experiments'' (2017), [[NHK]] documentary. Features interviews and recovered documentation from Unit&nbsp;731 personnel.
* "General Shiro" (2018), episode of ''[[The Blacklist]]''. Refers to [[Shirō Ishii]] and echoes Unit&nbsp;731's activities.
* ''[[Kamen Rider Black Sun]]'' (2022), Japanese Amazon Prime series. Features fictional experiments linked to Unit&nbsp;731, set in 1936.
* ''[[Gyeongseong Creature]]'' (2023), Korean drama on [[Netflix]]. Depicts biowarfare research during Japanese occupation of [[Gyeongseong]].

=== Video games ===
* ''[[Spooky's Jump Scare Mansion]]'' (2015). Features enemies implied to originate from Unit&nbsp;731–style experimentation.
* ''[[Call of Duty: Black Ops III]]'' (2015), Zombies mode. Introduces "Division 9", modeled on Unit&nbsp;731, with the KT-4 weapon labeled "731細菌戦の研究機関" ("Research Institution 731 of Bacterial Warfare").

== See also ==
{{portal|History|China|Japan}}

{{Div col|colwidth=22em}}
* [[American cover-up of Japanese war crimes]]
* {{anl|Battle of Changde}}
* {{anl|Comfort women}}
* [[History of biological warfare]]
* {{anl|History of chemical warfare}}
* {{anl|Human subject research}}
* {{anl|Kaimingjie germ weapon attack}}
* [[List of Japanese-run internment camps during World War II]]
* {{anl|Medical torture}}
* {{anl|Nazi human experimentation}}
* {{anl|Ōkunoshima}}
* {{anl|Operation Bloodstone}}
* {{anl|Project MKNAOMI}}
* {{anl|Unethical human experimentation}}
* {{anl|Unit 543}}
* {{anl|War crime}}
* [[War crimes in Manchukuo]]
* {{anl|Zhejiang-Jiangxi campaign}}
{{Div col end}}

== Explanatory notes ==
{{NoteFoot}}

== References ==
{{reflist}}

== Further reading ==

* Guillemin, Jeanne. ''Hidden Atrocities: Japanese germ warfare and American obstruction of justice at the Tokyo Trial'', Cornell University Press, 2017. {{ISBN|9780231183529}}.
* Barenblatt, Daniel. ''A Plague Upon Humanity: The Secret Genocide of Axis Japan's Germ Warfare Operation'', HarperCollins, 2004. {{ISBN|0060186259}}.
* Barnaby, Wendy. ''The Plague Makers: The Secret World of Biological Warfare'', Frog Ltd, 1999. {{ISBN|1883319854}}, {{ISBN|0756756987}}, {{ISBN|0826412580}}, {{ISBN|082641415X}}.
* Cook, Haruko Taya; Cook, Theodore F. ''Japan at war: an oral history'', New York: New Press: Distributed by Norton, 1992. {{ISBN|1565840143}}. Cf. Part 2, Chapter 6 on Unit 731 and Tamura Yoshio.
* Endicott, Stephen and Hagerman, Edward. ''The United States and Biological Warfare: Secrets from the Early Cold War and Korea'', Indiana University Press, 1999. {{ISBN|0253334721}}.
* Felton, Mark. ''The devil's doctors: Japanese Human Experiments on Allied Prisoners of War'', Pen & Sword, 2012. {{ISBN|978-1848844797}}
* Gold, Hal. ''Unit 731 Testimony'', Charles E Tuttle Co., 1996. {{ISBN|4900737399}}.
* Grunden, Walter E., ''Secret Weapons & World War II: Japan in the Shadow of Big Science'', University Press of Kansas, 2005. {{ISBN|0700613838}}.
* Handelman, Stephen and Alibek, Ken. ''Biohazard: The Chilling True Story of the Largest Covert Biological Weapons Program in the World{{snd}}Told from Inside by the Man Who Ran It'', Random House, 1999. {{ISBN|0375502319}}, {{ISBN|0385334966}}.
* Harris, Robert and Paxman, Jeremy. ''A Higher Form of Killing: The Secret History of Chemical and Biological Warfare'', Random House, 2002. {{ISBN|0812966538}}.
* Harris, Sheldon H. ''Factories of Death: Japanese Biological Warfare 1932–45 and the American Cover-Up'', Routledge, 1994. {{ISBN|0415091055}}, {{ISBN|0415932149}}.
* Lupis, Marco. "[http://www.repubblica.it/online/cronaca/virustre/fabbrica/fabbrica.html Orrori e misteri dell'Unità 731: la 'fabbrica' dei batteri killer]", ''La Repubblica'', 14 aprile 2003,
* Mangold, Tom; Goldberg, Jeff, [https://books.google.com/books?id=y69nhn-9FqcC ''Plague wars: a true story of biological warfare''], Macmillan, 2000. Cf. Chapter 3, Unit 731.
* Moreno, Jonathan D. ''Undue Risk: Secret State Experiments on Humans'', Routledge, 2001. {{ISBN|0415928354}}.
* Nie, Jing Bao, et al. ''Japan's Wartime Medical Atrocities: Comparative Inquiries in Science, History, and Ethics'' (2011) [https://www.amazon.com/Japans-Wartime-Medical-Atrocities-Transformations/dp/0415682282/ excerpt and text search]
* Tsuneishi, Keiichi (November 24, 2005). [https://apjjf.org/-Tsuneishi-Keiichi/2194/article.pdf "Unit 731 and the Japanese Imperial Army's Biological Warfare Program"]. ''The Asia-Pacific Journal''. Volume 3, Issue 11. Article ID 2194.
* Williams, Peter and Wallace, David. ''Unit 731: Japan's Secret Biological Warfare in World War II'', The Free Press, A Division of Macmillan, Inc., New York. 1989. {{ISBN|0029353017}}.
* Yang, Yan-Jun and Tam, Yue-Him. ''Unit 731: Laboratory of the Devil, Auschwitz of the East'', Fonthill Media., UK. 2018. {{ISBN|978-1781556788}}.

== External links ==
{{Sister project links}}
* [https://www.archives.gov/iwg/ The Nazi War Crimes and Japanese Imperial Government Records Interagency Working Group (IWG)] – The U.S. National Archives and Records Administration (NARA).
* [http://www.unit731.org/ History of the Unit 731] Unit 731 information site.
* [https://fas.org/nuke/guide/japan/bw/ History of Japan's biological weapons program] – The Federation of American Scientists (FAS).
* [https://web.archive.org/web/20150409024709/https://fas.org/nuke/guide/usa/cbw/bw.htm History of United States' biological weapons program] – The Federation of American Scientists (FAS).
* {{webarchive |url=https://web.archive.org/web/20071024123028/http://www.aiipowmia.com/ |date=October 24, 2007 |title=Unit 731: Auschwitz of the East }} – AII POW-MIA images.
* [http://www.centurychina.com/wiihist/confess/demondoc.html ''Army Doctor''] – a firsthand account by Yuasa Ken.
* [http://people.bu.edu/wwildman/WeirdWildWeb/courses/thth/projects/thth_projects_2003_parkeun.htm ''Theodicy – Through the Case of "Unit 731"''] by Eun Park (2003).
* [http://www.abc.net.au/news/2005-08-15/us-paid-for-japanese-human-germ-warfare-data/2080618 "US paid for Japanese human germ warfare data"], Australian Broadcasting Corporation News Online.
* [https://www.theguardian.com/elsewhere/journalist/story/0,7792,1338296,00.html ''Japan's sins of the past''] by Justin McCurry (2004), ''The Guardian''.
* [http://www.theage.com.au/articles/2002/08/28/1030508070534.html "The Asian Auschwitz of Unit 731"] by Shane Green (2002), ''The Age''.
* {{YouTube|Qfy5TMbueSM|''The Truth of Unit 731: Elite medical students and human experiments''}}, a documentary by NHK (2017){{Webarchive|url=https://web.archive.org/web/20220124131735/http://materiaislamica.com/index.php/The_Unknown_Muslim_Victims_of_Japanese_Unit_731_in_WWII_(1932%E2%80%941945) |date=24 January 2022 }}
* [https://www.archives.gov/files/iwg/japanese-war-crimes/select-documents.pdf Select Documents on Japanese WarCrimes and Japanese Biological Warfare, 1934–2006]
* [http://czasopisma.ltn.lodz.pl/index.php/Prace-Polonistyczne/article/view/1066 Unit 731 in Polish literature]
* [https://tv.cctv.com/2015/09/01/VIDE1441071222552557.shtml ''731''] (2015), a documentary by [[China Central Television|CCTV]]

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