View source for Onsen

{{Short description|Japanese hot springs}}
{{Italic title|reason=[[:Category:Japanese words and phrases]]}}
{{Use dmy dates|date=December 2018}}
[[File:Onsen in Nachikatsuura, Japan.jpg|thumb|Outdoor ''onsen'' at Nakanoshima in [[Nachikatsuura, Wakayama]]]]
[[File:Onsen-rotenburo-winter2014.ogv|thumb|thumbtime=9|A video showcasing the stool and shower used for cleaning off, an inside pool and an outside pool]]

In Japan, {{Nihongo||[[wikt:温泉|温泉]]|'''''onsen'''''|{{ipa|ja|oɰ̃seɴ|pron}}}} are [[hot spring]]s and the bathing facilities and [[Ryokan (inn)|traditional inns]] around them. There are approximately 25,000 hot spring sources throughout Japan, and approximately 3,000 ''onsen'' establishments use naturally hot water from these [[Geothermal gradient|geothermal]]ly heated springs.<ref name="Sacred Waters">{{cite book |last1=Erikson |first1=August |last2=Masui |first2=Anette |title=Sacred Waters: A Guide to Japanese Hot Springs |date=2014 |publisher=Votum Forlag AB |location=Karlstad, Sweden |isbn=978-91-87283-33-8 |page=88 }}</ref>

''Onsen'' may be either {{Nihongo|outdoor baths|露天風呂 or 野天風呂|roten-buro / noten-buro}} or {{Nihongo|indoor baths|内湯|uchiyu}}. Traditionally, ''onsen'' were located outdoors, although many inns have now built indoor bathing facilities as well. Nowadays, as most households have their own baths, the number of traditional public baths has decreased,<ref>{{cite web |title=Public Baths in Japan |url=https://www.japan-guide.com/e/e2074.html |website=www.japan-guide.com |access-date=17 October 2018 |language=en}}</ref> but the number and popularity of {{Nihongo|hot spring resort towns|[[:ja:温泉街|温泉街]]|onsen-gai}} have increased since the end of [[World War II|Second World War]].<ref name=":10">{{Cite web |title=温泉の歴史（現代）※第二次世界大戦後 {{!}} 日本温泉協会 |url=https://www.spa.or.jp/onsen/589/ |access-date=2024-07-25 |website=一般社団法人 日本温泉協会 ～温泉名人～ |language=ja}}</ref> Baths may be either publicly run by a municipality or privately, often connecting to a lodging establishment such as a hotel, ''[[Ryokan (inn)|ryokan]]'', or ''[[Ryokan (inn)#Minshuku|minshuku]]''. [[File:Kaisenkaku Asamushi Onsen Aomori Japan02n.jpg|thumb|Indoor ''onsen'' at [[Asamushi Onsen]]]]

The presence of an ''onsen'' is often indicated on signs and maps by the symbol ♨, the [[kanji]] {{linktext|湯}} (''yu'', meaning "hot water"), or the simpler phonetic [[hiragana]] character ゆ (''yu'').

==Definition==
According to the Japanese {{Nihongo|Hot Springs Act|[[:ja:温泉法|温泉法]]|Onsen Hō}}, ''onsen'' is defined as "hot water, mineral water, and [[water vapor]] or other gas (excluding [[natural gas]] of which the principal component is [[hydrocarbon]]) gushing from underground".<ref>{{Cite web|title=Hot Spring Act|url=https://www.env.go.jp/nature/onsen/pdf/2-5_p_1.pdf|access-date=2020-10-18|publisher=Ministry of the Environment Government of Japan}}</ref> The law states that mineralized hot spring water that feeds an ''onsen'' must be at least {{convert|25|C}} originating at a depth of at least {{convert|1.5|km}}, and contain specified amounts of minerals such as sulphur, sodium, iron, or magnesium.<ref name="Sacred Waters" />Even if it does not meet this definition, if the spring water is suitable for bathing, it is considered a "hot spring" in most cases. However, in that case, there are restrictions on the health benefits that the owner of the spring can claim.

When ''onsen'' water contains distinctive minerals or chemicals, establishments often display what type of water it is,<ref>{{Cite journal|last1 =Serbulea|first1 =Mihaela| last2 = Payyappallimana|first2 = Unnikrishnan|title=Onsen (hot springs) in Japan—Transforming terrain into healing landscapes|journal = Health & Place|volume =18|issue =6|pages =1366–73|doi =10.1016/j.healthplace.2012.06.020|pmid =22878276|year =2012}}</ref> in part because the specific minerals found in the water have been thought to provide health benefits.<ref name="Nippon">{{cite web |last1=Tadanori |first1=Matsuda |title=Soaking up the Benefits: Japan's Hot Springs Tradition |date=30 March 2015 |url=https://www.nippon.com/en/views/b04702/ |publisher=Nippon: Your doorway to Japan |access-date=27 August 2020}}</ref> Types include {{Nihongo|sulfur ''onsen''|硫黄泉|iō-sen}}, {{Nihongo|sodium chloride ''onsen''|ナトリウム泉|natoriumu-sen}}, {{Nihongo|hydrogen carbonate ''onsen''|炭酸泉|tansan-sen}}, and {{Nihongo|iron ''onsen''|鉄泉|tetsu-sen}}.

== History ==
Exactly when humans first began bathing in ''onsen'' in Japan is unknown, but historical records show it has a history of at least about 1,300 years.<ref name=":7">{{Cite web |title=温泉の歴史（古代）※奈良時代～平安時代 {{!}} 日本温泉協会 |url=https://www.spa.or.jp/onsen/568/ |access-date=2024-07-30 |website=一般社団法人 日本温泉協会 ～温泉名人～ |language=ja}}</ref><ref name=":8">{{Cite web |title=第1章 湯治場としての温泉 |url=https://www.ndl.go.jp/kaleido/entry/23/1.html |access-date=2024-07-30 |website=「本の万華鏡」第23回「本から広がる温泉の世界」 |language=ja}}</ref> Many of the earliest records of ''onsen'' bathing document [[Emperor of Japan|Japanese Emperors]] or members of the [[Imperial House of Japan|imperial family]] staying at ''onsen'' for long periods of time. At the time, ''onsen'' were thought to be sacred and to have healing properties.<ref name=":9">{{Cite web |title=古代から現代へ：日本の温泉文化の歴史 |url=https://onsenfudousan.com/cms/slog/entry/5 |access-date=2024-07-30 |website=温泉不動産 |language=ja}}</ref> It is now believed those who traveled to ''onsen'' in these early records were seeking cures to disease or other ailments by bathing in the ''onsen'' water.<ref name=":8" /> This ancient practice of bathing in ''onsen'' to cure illnesses, often for long periods such as a week, is referred to as ''tōji'' ([[:ja:湯治|湯治]]).<ref>{{Cite web |date=2015-03-04 |title=温泉は日本の文化である |url=https://www.nippon.com/ja/views/b04702/ |access-date=2024-07-30 |website=nippon.com |language=ja}}</ref> Some of the oldest ''onsen'' in Japan are considered to be [[Dōgo Onsen|Dogo Onsen]] in [[Ehime Prefecture]], [[Nanki-Shirahama Onsen|Shirahama Onsen]] in [[Wakayama Prefecture]], and [[Arima Onsen]] in [[Hyōgo Prefecture|Hyogo Prefecture]].<ref name=":7" />

Until around the [[Edo period]], ''onsen'' had close religious ties to [[Buddhism in Japan|Buddhism]] with [[Buddhist temples in Japan|temples]] often being built near ''onsen'' sources.<ref name=":8" /><ref name=":9" /> During the Edo period, however, ''onsen'' began to gain popularity among the general population thanks in part to depictions of the hot springs in ''[[ukiyo-e]]''.<ref name=":8" /><ref name=":9" /> It is also during this period that the use of ''onsen'' shifted from being primarily for religious and healing reasons to being used for bathing for cleanliness and socializing.<ref>{{Cite web |last=にっぽんの温泉観光事典 |date=2014-04-19 |title=日本の温泉の歴史-宗教的意味、戦国時代と江戸時代 |url=https://onsen.kankoujp.com/onsen-history/ |access-date=2024-07-30 |website=にっぽんの温泉観光事典 |language=ja}}</ref><ref name=":11">{{Cite web |title=Learn about Japanese hot spring culture |url=http://www.studyjapan.jp/en/topics/culture/hot-spring.html |access-date=2024-07-30 |website=アクセス日本留学 |language=en}}</ref>

In modern times, traveling to {{Nihongo|hot spring resort towns|[[:ja:温泉街|温泉街]]|onsen-gai}} is a popular form of [[domestic tourism]] in Japan.<ref name=":10" /> During the [[Japanese asset price bubble|bubble economy]] of the 1980s, there was a "''onsen'' boom."<ref name=":10" /> Although the number of overnight guests at hot spring resorts has decreased slightly since the boom, travel to such ''onsen'' towns as a relaxing getaway is still popular among Japanese people.<ref name=":10" /><ref name=":11" />

==Mixed bathing==
[[File:Guidebook to Hakone 1811a.jpg|thumb|Guidebook to [[Hakone]] from 1811]]

Traditionally, men and women bathed together at both ''onsen'' and ''[[sentō]]'' communal bathhouses, but gender separation has been enforced at most institutions since the opening of Japan to the West during the [[Meiji Restoration]]. 

{{Nihongo|[[Mixed bathing]]|混浴|kon'yoku}} is currently banned in Japanese public baths.<ref name = MHLW>厚生労働省「公衆浴場における衛生管理理要領等の改正について〔公衆浴場法〕」(生食発1210第1号)(Retrieved June 3 2024) https://www.mhlw.go.jp/web/t_doc?dataId=00tc5492&dataType=1&pageNo=1</ref><ref name = shuken>[https://www.shuken.jp/column/onyoku/onyoku-law/4807/#:~:text=%E5%AE%9F%E3%81%AF%E3%80%81%E5%85%AC%E8%A1%86%E6%B5%B4%E5%A0%B4%E6%B3%95%E3%81%AB,%E3%81%A8%E6%98%8E%E8%A8%98%E3%81%97%E3%81%A6%E3%81%84%E3%81%BE%E3%81%99%E3%80%82 "サウナの男女混浴は法律でどうなってる？公衆浴場法・条例を調べてみた"] retrieved June 3 2024</ref>{{efn|shuken=fn1| due to varying interpretations of terminology and local ordinances, rare instances of mixed bathing still exist at places like [[:ja:鶴の湯温泉 (秋田県)|Tsurunoyu Onsen]] where the water is [[Opacity (optics)|opaque]].<ref>[http://www.tsurunoyu.com/english.html "Tsurunoyu Onsen"] Retrieved June 3 2024</ref>}}<ref>｢混浴ダメ！｣何歳から？ 10歳→7歳、国が通知 [https://www.nishinippon.co.jp/item/n/703573/ 西日本新聞] Retrieved June 3 2024 </ref> Depending on the [[Prefectures of Japan|prefecture]] and local ordinances, children seven years old and younger may be exempt from this ban.<ref name="MHLW" /> 

Private ''onsen'' called {{Nihongo|"family baths"|[[:jp:家族風呂|家族風呂]]|kazokuburo}} can be found in many locations throughout Japan. These can be reserved and used for mixed bathing.<ref>[https://yuasobi.com/blog/12 "日帰り家族風呂を満喫するなら！知っておくべき混浴に関する条例"] Retrieved June 3 2024</ref>

In the [[Japanese language]], {{Nihongo|2=女/おんな|3="Onna"}} means [[Woman]] and {{Nihongo|2=男/おとこ|3="Otoko"}} means [[Man]].  The characters {{Nihongo2|ゆ}} and {{Nihongo2|湯}} (pronounced yu) stands for [[Hot water]], but also for a [[Bathing]] or ''Onsen''.  Generally, there is a separation called {{Nihongo|[[Noren]]|暖簾/のれん}}<ref>{{Cite web |title=A Beginner's Guide to Onsen |url=https://www.japan.travel/en/ph/story/onsen-etiquette/ |access-date=2025-03-01 |website=Japan National Tourism Organization (JNTO) |language=en-ph}}</ref> curtains.

==Etiquette==
[[File:Onsen-2-Clothes.jpg|thumb|Baskets]]

Onsen are a location where considerable offense can be caused if the proper social etiquette is not observed. The general procedure and expected etiquette closely resemble those used at a [[sento]]  certain hours where outsiders may purchase day passes to enter. Standalone onsen open to the public also exist. Onsen are considered more of a special experience than the sento, which is used for common bathing. Due to their integrated location within a hotel, an entry attendant is rare and bathers will usually wear the hotel-provided [[yukata]] and indoor slippers to walk from their rooms to the onsen. Towels are provided to guests at the entry, and shower stations and vanities are fully stocked with toiletries and conveniences for bather's use, instead of guests being required to bring their own or purchase such items separately. Guests should not take wet towels or toiletries back with them or hoard the complimentary items. While it is common after a bath in the sento to quickly re-shower before leaving, many onsen bathers skip this second shower to keep the minerals from the hot spring on their skin. Onsen within ryokan or hotels are generally kept open 24 hrs a day, or only closed for a brief daily cleaning period, to allow guests to freely bathe in the middle of the night if the whim takes them. Popular, private, or specialized baths may require reservations or additional fees. 

===Ensuring cleanliness===
As at a ''sentō'',  at an ''onsen'', all guests are expected to wash and rinse themselves thoroughly before entering the hot water. Bathing stations are equipped with stools, faucets, rinsing basins, and complimentary toiletries such as soap and shampoo; nearly all onsen also provide removable shower heads for rinsing convenience. Entering the ''onsen'' while still dirty or with traces of soap on the body is socially unacceptable.{{efn|In very isolated, undeveloped, natural onsen, where there is no possibility to use soap before entering in the bath, onsen users are expected to at least rinse their body with the water of the bath before entering it.}}

One's hair should never touch the bath water and should be worn up.

Even though onsen can be a luxury experience and environment, guests are still expected to clean up after themselves by staying tidy and rinsing off their shower area for the next guest.

===Swimsuits===
Guests are not allowed to wear [[Swimsuit|swimsuits]] in the baths or showers and must be completely nude. 

The only time swimsuits are allowed and required are in specific modern pools which allow both men and women to use them together, but many of these mixed ''onsen'' resemble more of a [[swimming pool|pool]] or [[Water park|waterpark]] than the traditional idea of an ''onsen''.<ref>[https://onsen.nifty.com/onsen-matome/220304902694/ "温水プールが楽しい！西日本の温泉・お風呂テーマパーク15選"] Retrieved June 4 2024</ref><ref>[https://jw-webmagazine.com/tips/onsen-towns-near-tokyo/ "5 Swimwear-allowed Onsen Spots near Tokyo"] ''JW Web Magazine'' Retrieved June 4 2024</ref><ref>[https://www.yunessun.com/yunessun/ "Yunessun"] Retrieved June 4 2024</ref><ref name="Hadfield">{{cite news|last=Hadfield |first=James |title=Last splash: Immodest Japanese tradition of mixed bathing may be on the verge of extinction |url=https://www.japantimes.co.jp/life/2016/12/10/lifestyle/last-splash-immodest-japanese-tradition-mixed-bathing-may-verge-extinction/#.XAkRgXQza00|work=[[The Japan Times]] |date= 10 December 2016 | access-date=6 December 2018}}</ref>

===Towel===
''Onsen'' guests generally have a small towel with them to use as a drying cloth, since re-entering the changing area while dripping wet is a faux-pas. The towel can also provide a modicum of [[modesty]] when walking between the washing area and the baths by holding it loosely in front of your genitals. Though many TV shows depict characters wearing a towel in the bath, this is a television invention used for actor modesty and wearing towels into the bath is forbidden. It is against the rules to immerse or dip towels in the ''onsen'' bath water, since this is considered unclean. People normally set their towels off to the side of the water when enjoying the baths, or place their folded towels on top of their heads to keep them out of the water.{{Citation needed|date=March 2025}}

===Tattoos===
By 2015, around half (56%) of ''onsen'' operators had banned bathers with [[tattoo]]s from using their facilities.<ref name=Ryall>{{cite news|url=https://www.scmp.com/news/asia/east-asia/article/1876200/japanese-owners-famous-onsen-hot-springs-soften-their-stance|title=Japanese owners of famous 'onsen' hot springs soften their stance on tattoo ban to appease foreign visitors|first=Julian|last=Ryall|date=6 November 2015|archive-url=https://web.archive.org/web/20160117035103/http://www.scmp.com/news/asia/east-asia/article/1876200/japanese-owners-famous-onsen-hot-springs-soften-their-stance|archive-date=17 January 2016}}</ref><ref>{{cite news|url=http://www.japantimes.co.jp/community/2012/11/06/how-tos/if-you-need-to-bring-drugs-to-japan-sort-out-the-paperwork-or-else/#.Vqv4xK3ouUk|newspaper=The Japan Times|date=6 November 2012|first=Ashley|last=Thompson|title=If you need to bring drugs to Japan, sort out the paperwork — or else|archive-url=https://web.archive.org/web/20150719081838/http://www.japantimes.co.jp/community/2012/11/06/how-tos/if-you-need-to-bring-drugs-to-japan-sort-out-the-paperwork-or-else#.Vqv5A63ouUl|archive-date=19 July 2015}}</ref><ref>{{cite web|author=Xeni Jardin|url=http://boingboing.net/2009/12/22/tattoo-in-japan.html |title=Tattoo in Japan |publisher=Boing Boing |date=22 December 2009|archive-url=https://web.archive.org/web/20091224074209/http://www.boingboing.net/2009/12/22/tattoo-in-japan.html|archive-date=24 December 2009}}</ref> The original reason for the tattoo ban was to keep out ''[[yakuza]]'' and members of other crime gangs who traditionally have elaborate full-body decoration.<ref>{{citation|url=https://naganonow.com/nagano-onsen-japan/#onsen_warnings|title=Onsen Warnings and Hassles |date=July 2019 |access-date=30 September 2020 |language=en}}</ref> In 2016, the [[Japan Tourism Agency]] urged ''onsen'' operators to allow foreign customers with tattoos to use the ''onsen'' on a conditional basis in order to accommodate the increasing number of foreign tourists.<ref>{{cite web|url=https://www.mhlw.go.jp/content/001165667.pdf|archive-url=https://web.archive.org/web/20250306104324/https://www.mhlw.go.jp/content/001165667.pdf|script-title=ja:入れ墨（タトゥー）がある外国人旅行者の入浴に関する対応について|language=ja|publisher=[[Japan Tourism Agency]]|date=18 March 2016|archive-date=6 March 2025|access-date=6 March 2025}}</ref> On the other hand, ''onsen'' operators wanted foreign customers to enjoy the ''onsen'', but were concerned that allowing foreign customers with tattoos to use the ''onsen'' would prevent them from keeping ''yakuza'' out of the ''onsen''.<ref>{{cite web|url=https://www.sankei.com/article/20150806-4MJEIM5OR5PTRD6F5XQQATTZ5Q/|script-title=ja:「タトゥーお断り WHY?」外国人観光客、温泉で当惑 2019ラグビーW杯はどうなの？|language=ja|publisher=[[Sankei Shimbun]]|date=6 August 2015|access-date=6 March 2025}}</ref><ref>{{cite web|url=https://news.livedoor.com/article/detail/22256473/|archive-url=https://web.archive.org/web/20250306104300/https://news.livedoor.com/article/detail/22256473/|script-title=ja:入れ墨で温泉お断り？暴力団排除条例と外国人観光客増加の間でゆれる福岡・公衆入浴施設の対応|language=ja|publisher=Livedoor News|date=30 March 2022|archive-date=6 March 2025|access-date=6 March 2025}}</ref>

However, tattoo-friendly ''onsen'' do exist.<ref>{{cite news|url=http://www.japantimes.co.jp/community/2012/11/27/how-tos/ink-doesnt-always-cause-a-stink-at-the-onsen/#.Vqv1nq3ouUk|first=Ashley|last=Thompson|title=Ink doesn't always cause a stink at the onsen|newspaper=The Japan Times|date=27 November 2012|archive-url=https://web.archive.org/web/20150719082949/http://www.japantimes.co.jp/community/2012/11/27/how-tos/ink-doesnt-always-cause-a-stink-at-the-onsen#.Vqv4hq3ouUl|archive-date=19 July 2015}}</ref> A 2015 study by the Japan National Tourism Organisation found that more than 30% of ''onsen'' operators at hotels and inns across the country will not turn someone with a tattoo away; another 13% said they would grant access to a tattooed guest under certain conditions, such as having the tattoo covered up.<ref name=Ryall/> Some towns have many tattoo-friendly ''onsen'' that do not require guests to cover them up. Two such towns are [[Kinosaki, Hyōgo|Kinosaki Onsen]] in Hyōgo and [[Beppu Onsen]] in Ōita.<ref>{{Cite web|url=https://travel.gaijinpot.com/japan-sightseeing-essentials/30-tattoo-friendly-onsen-in-japan/|title = 30 Tattoo Friendly Onsen in Japan}}</ref>

With the increase in foreign customers due to growing tourism, some ''onsen'' that previously banned tattoos are loosening their rules to allow guests with small tattoos to enter, provided they cover their tattoos with a patch or sticking plaster.<ref name=Ryall/><ref>{{cite news|url=http://en.rocketnews24.com/2015/04/17/onsen-in-nagano-will-now-welcome-foreigners-with-tattoos-as-long-as-they-patch-em-up/|title=Onsen in Nagano will now welcome foreigners with tattoos, as long as they patch 'em up|date=17 April 2015|first=Evie|last=Lund|archive-url=https://web.archive.org/web/20151214210842/http://en.rocketnews24.com/2015/04/17/onsen-in-nagano-will-now-welcome-foreigners-with-tattoos-as-long-as-they-patch-em-up/|archive-date=14 December 2015}}</ref>

== Benefits ==
There are various health benefits attributed to bathing in ''onsen''.<ref name=":0">{{Cite web |title=特集「ヘルシートーク」 {{!}} ソニー生命保険株式会社 |url=https://cs.sonylife.co.jp/lpv/pcms/sca/ct/special/topic/index1612.html?lpk=63333 |access-date=2024-07-25 |website=cs.sonylife.co.jp |language=ja}}</ref><ref name=":1">{{Cite web |title=温泉利用が健康づくりにもたらす総合的効果についてのエビデンスに関する研究 {{!}} 厚生労働科学研究成果データベース |url=https://mhlw-grants.niph.go.jp/project/23931 |access-date=2024-07-25 |website=mhlw-grants.niph.go.jp}}</ref><ref name=":2">{{Cite web |title=だから温泉はカラダにいい {{!}} 温泉医科学研究所 |url=https://www.onsen-msrc.com/knowledge/contents/dakara.html |access-date=2024-07-25 |website=www.onsen-msrc.com}}</ref> ''Onsen'' are particularly renowned for their relaxing and [[Therapeutic effect|therapeutic effects]].<ref name=":2" /> These effects are due to properties such as the temperature, pressure, and mineral composition of the water.<ref>{{Cite web |title=体のこわばり緩和、むくみ改善 ～温泉による科学的な効果（国際医療福祉大学大学院 前田眞治教授）～ |url=https://medical.jiji.com/topics/2878 |access-date=2024-07-25 |website=時事メディカル |language=ja}}</ref> 

A 2014 study conducted in [[Beppu]], a city famous for its ''onsen'', found that regular bathing in ''onsen'' has various health benefits such as lowering [[blood pressure]], improving [[Blood circulation|circulation]] and cardiovascular health, reducing chronic pain and fatigue, and lowering the rate of [[Depression (mood)|depression]].<ref name=":1" /> A survey conducted in [[Atami]], another city famous for its ''onsen'', found that individuals with ''onsen'' in their homes were less likely to take blood pressure medication than those without ''onsen''.<ref name=":0" />

There are various types of ''onsen'' including [[Carbonated water|carbonated]] springs, [[iron]]-containing springs, [[Acid|acidic]] springs, strong-smelling [[sulfur]] springs, among others.<ref name=":0" /> Each type of ''onsen'' is believed to have unique benefits. Carbonated springs, for example, are believed to lead to smooth skin.<ref name=":0" /> ''Onsen'' facilities often advertise various health and beauty benefits they claim their water to provide.<ref>{{Cite web |title=温泉浴場のご案内{{pipe}}源泉100%かけ流しの「ひょうたん温泉」 |url=https://www.hyotan-onsen.com/onsen/index.html#data |access-date=2024-07-25 |website=www.hyotan-onsen.com}}</ref><ref>{{Cite web |title=蔵王温泉大露天風呂 |url=https://www.jupeer-zao.com/roten/ |access-date=2024-07-25 |website=www.jupeer-zao.com}}</ref> 

Water at some ''onsen'' facilities is drinkable.<ref name=":3">{{Cite web |title=飲泉について {{!}} 日本温泉協会 |url=https://www.spa.or.jp/onsen/528/ |access-date=2024-07-25 |website=一般社団法人 日本温泉協会 ～温泉名人～ |language=ja}}</ref><ref name=":4">{{Cite web |title=温泉水は飲める？温泉の定義と、温泉水の上手な飲み方 {{!}} 水と健康の情報メディア{{pipe}}トリム・ミズラボ - 日本トリム |url=https://www.nihon-trim.co.jp/media/18455/ |access-date=2024-07-25 |website=www.nihon-trim.co.jp}}</ref><ref name=":5">{{Cite web |title=飲泉{{pipe}}源泉100%かけ流しの「ひょうたん温泉」 |url=https://www.hyotan-onsen.com/onsen/index.html#drink |access-date=2024-07-25 |website=www.hyotan-onsen.com}}</ref> ''Onsen'' water should only be consumed if it is confirmed to be safe to drink by the prefecture.<ref name=":4" /> The water should be obtained from a designated drinking source that is separate from the water which is bathed in.<ref name=":4" /> The often mineral-rich ''onsen'' water is believed to have benefits such as treating [[iron-deficiency anemia]] or [[constipation]].<ref name=":3" /><ref name=":5" />

==Risks==
Article 18, paragraph 1 of the Japanese Hot Springs Act publishes guidance on contraindications and cautions for bathing in hot springs, and drinking their respective waters.<ref name="JHS Act">{{cite web |title=The Criteria for the Notification, etc. on Contraindications and Cautions for Bathing and Drinking as specified in Article 18, Paragraph 1 of the Hot Springs Act |url=https://www.env.go.jp/content/900453265.pdf |website=Ministry of the Environment: Government of Japan |access-date=28 October 2022}}</ref>  Although millions of Japanese bathe in ''onsen'' every year with few noticeable side effects, there are still potential side effects to ''onsen'' usage, such as aggravating high blood pressure or heart disease.<ref>{{cite web|url=http://www.city.beppu.oita.jp/01onsen/english/03hyakka/ryouyou.html |title=Hot Spring Treatment{{pipe}}Hot Spring Encyclopedia{{pipe}}ONSEN{{pipe}}BEPPU CITY{{pipe}} |publisher=City.beppu.oita.jp |access-date=7 December 2010}}</ref>

''[[Legionella]]'' bacteria have been found in some ''onsen'' with poor sanitation.<ref>{{cite journal |title=Molecular determination of infection source of a sporadic Legionella pneumonia case associated with a hot spring bath |author=H. Miyamoto |author2=S. Jitsurong |author3=R. Shiota |author4=K. Maruta |author5=S. Yoshida |author6=E. Yabuuchi  |journal=Microbiol. Immunol. |volume=41 |issue=3 |pages=197–202 |year=1997 |pmid=9130230 |doi=10.1111/j.1348-0421.1997.tb01190.x|s2cid=25016946 |doi-access=free }}</ref><ref name="hiuga">{{cite journal |title=An outbreak of legionellosis in a new facility of hot spring Bath in Hiuga City |author=Eiko Yabuuchi |author2=Kunio Agata |issn=0387-5911  |volume=78 |issue=2 |pages=90–98 |year=2004 |journal=Kansenshogaku Zasshi |doi=10.11150/kansenshogakuzasshi1970.78.90 |pmid=15103899|doi-access=free }}</ref> For example, 295 people were infected with Legionella and seven died at an ''onsen'' in [[Miyazaki Prefecture]] in 2002.<ref name="hiuga"/><ref name="Shueisha111069">{{cite web |url=https://shueisha.online/newstopics/111069 |title=「怖い菌ではないと思っていた」と運営会社社長。過去には7名死亡した事例も |language=ja |publisher=[[Shueisha]] |access-date=4 March 2023 |archive-date=1 March 2023 |archive-url=https://web.archive.org/web/20230301133909/https://shueisha.online/newstopics/111069 |url-status=dead }}</ref>{{efn|In addition to this case, two people were infected and one died at [[Arima Onsen]] in 2022. In the same year, Legionella bacteria up to 3,700 times the standard value were detected at an ''onsen'' in [[Fukuoka Prefecture]] because the water was changed only twice a year.<ref name="Shueisha111069"/>}} Revelations of poor sanitary practices at some ''onsen'' have led to improved regulation by hot-spring communities to maintain their reputation.<ref name="search.japantimes.co.jp">{{cite news |title=Onsen: know what you're getting into |newspaper=The Japan Times |url= http://search.japantimes.co.jp/cgi-bin/nn20040814a5.html}}</ref>

There have been reports of [[Thermophile|infectious disease]] found in hot bodies of water worldwide, such as various ''[[Naegleria]]'' species.<ref name="Shinji Izumiyama 2003 514">{{cite journal |title=Occurrence and Distribution of Naegleria Species in Thermal Waters in Japan |author=Shinji Izumiyama |author2=Kenji Yagita |author3=Reiko Furushima-Shimogawara |author4=Tokiko Asakura |author5=Tatsuya Karasudani |author6=Takuro Endō  |journal=The Journal of Eukaryotic Microbiology |volume=50 |issue=s1 |date=July 2003 |doi=10.1111/j.1550-7408.2003.tb00614.x |pmid=14736147 |pages=514–5|s2cid=45052636 }}</ref> While studies have found the presence of ''Naegleria'' in hot spring waters, ''[[Naegleria fowleri]]'', responsible for numerous fatal cases of [[Primary amoebic meningoencephalitis|primary amoebic meningoencephalitis]] around the world, has not been found to be present in the water at ''onsen''.<ref name="Shinji Izumiyama 2003 514"/> Nevertheless, fewer than five cases have been seen historically in Japan, although not conclusively linked to ''onsen'' exposure.<ref>{{cite journal |title=Primary amebic meningoencephalitis due to Naegleria fowleri: An autopsy case in Japan |author=Yasuo Sugita |author2=Teruhiko Fujii |author3=Itsurou Hayashi |author4=Takachika Aoki |author5=Toshirō Yokoyama |author6=Minoru Morimatsu |author7=Toshihide Fukuma |author8=Yoshiaki Takamiya |journal=Pathology International |volume=49 |date=May 1999 |doi=10.1046/j.1440-1827.1999.00893.x |pmid=10417693 |issue=5 |pages=468–70|s2cid=21576553 }}</ref>

Many ''onsen'' display notices reminding anyone with open cuts, sores, or lesions not to bathe. Additionally, in recent years onsen have been increasingly adding [[chlorine]] to their waters to prevent infection, although many ''onsen'' purists seek natural, unchlorinated ''onsen'' that do not recycle their water but instead clean the baths daily.<ref name="search.japantimes.co.jp"/> These precautions as well as proper ''onsen'' usage (i.e. not placing the head underwater, washing thoroughly before entering the bath) greatly reduce any overall risk to bathers.

[[Voyeurism]] is reported at some ''onsen''. In 2016, [[The Japan Times]] reported that this was mitigated in some [[prefectures of Japan]] where nude mixed bathing is not permitted, and that visitors must wear [[swimsuit]]s.<ref name="Hadfield"/><ref>{{cite news |date=2021-11-21 |title=盗撮の実態、知っていますか？ 10年で倍増/常習化しやすく 被害に遭わないためには...【NEXT特捜隊】 |url=https://www.at-s.com/news/article/shizuoka/988762.html |language=ja |work=[[Shizuoka Shimbun]] |access-date=2022-10-28}}</ref><ref>{{cite news |date=2018-12-28 |title=＜盗撮の闇(3)＞奪われた日常 被害者、映像流出におびえ |url=https://www.saga-s.co.jp/articles/-/319829 |language=ja |work=佐賀新聞 |access-date=2022-10-28}}</ref> In 2021, several people were arrested in connection with an organized group accused of taking photos of women in open-air baths.<ref>[https://bunshun.jp/articles/-/54043 "盗撮のカリスマ"斎藤果林容疑者が逮捕 犯行グループの一員が明かす"卑劣な手口"「若い女性が集まる連休にはグループで"温泉盗撮旅"へ] ''Bunshun Online'' (in Japanese) May 1 2022. Retrieved June 3 2024. </ref><ref>[https://www.yomiuri.co.jp/national/20230201-OYT1T50285/ "「盗撮のカリスマ」率いるグループ16人摘発...男「30年前から1万人は盗撮」"] ''[[Yomiuri Shimbun]]'' (in Japanese) February 2 2023. Retrieved June 3 2024.</ref>

== Bathing methods ==
In addition to typical {{Nihongo|'''large public baths'''|[[:jp:大浴場|大浴場]]|daiyokujō}} and {{Nihongo|'''outdoor baths'''|[[:jp:露天風呂|露天風呂]]|roten-buro)}}, there are various other methods of experiencing ''onsen'' that can be found at various facilities throughout Japan. Examples include:
* '''{{Nihongo|Waterfall baths|[[:jp:打たせ湯|打たせ湯]]|utase-yu}}''': hot water is released from an elevated position and the pressure of the water has a [[massaging]] effect.<ref name=":6">{{Cite web |title=Other types of bathing {{!}} Onsen Medical Science Reserch Center |url=https://www.onsen-msrc.com/kenko_f/onsen_english/toku/toku1.html |access-date=2024-07-25 |website=www.onsen-msrc.com}}</ref>[[File:垂玉温泉打たせ湯.jpg|thumb|''Utase-yu'' waterfall bath at Tarutama Onsen ([[:ja:垂玉温泉|垂玉温泉]])]]
* '''{{Nihongo|Steam baths|蒸し湯|mushi-yu}}''': ''onsen'' steam is released in either a small room or a "steam box" (in which one immerses their body up to their neck) which has an effect similar to a [[sauna]].<ref name=":6" />
* '''{{Nihongo|Sleeping baths|寝湯|ne-yu}}''': shallow baths in which one lies down. These can be used for sleeping, but there is a risk of overheating.<ref>{{Cite web |title=寝湯とは？最高のくつろぎ空間が堪能できる温泉10選！{{pipe}}ニフティ温泉 |url=https://onsen.nifty.com/onsen-matome/230613707757/ |access-date=2024-07-25 |website=ニフティ温泉 |language=ja}}</ref>
* '''{{Nihongo|[[Ashiyu]]|足湯|ashi-yu}}''': these are usually separate from main ''onsen'' facilities and are typically free. As only the feet and lower legs are immersed in the ''onsen'' water, users are otherwise fully clothed.
* '''{{Nihongo|Sand baths|[[:jp:砂湯|砂湯]]|suna-yu}}''': an individual lies in or is buried partially in [[sand]] which is heated by ''onsen'' water or another source.<ref name=":6" /> ''[[Yukata]]'' are usually worn in the sand baths and they are mixed-gender.
* '''{{Nihongo|[[Ganban'yoku]]|岩盤浴|}}''': heated stones on which visitors lie down while wearing {{Nihongo|kannaigi|館内着}}, or a type of casual Japanese indoor wear.<ref>{{Cite web |title=岩盤浴での持ち物は？入り方や服装を解説 おすすめの岩盤浴施設も紹介{{pipe}}ニフティ温泉 |url=https://onsen.nifty.com/onsen-matome/240125094738/ |access-date=2024-07-25 |website=ニフティ温泉 |language=ja}}</ref> As clothing is worn in ''ganban'yoku,'' they are mixed-gender and located in a separate location from the nude bathing area of an ''onsen'' facility. 
[[Sauna|Saunas]] are also sometimes located at ''onsen'' bathing facilities. A relatively cold bath called  {{Nihongo|mizu-buro|水風呂}} is often located directly outside a facility's sauna to allow users to quickly cool down. The cycle of entering hot baths, saunas, and cold baths at an ''onsen'' facility is sometimes referred to as {{Nihongo|totonou|ととのう}} and is believed to be refreshing and to have health benefits.<ref>{{Cite web |date=2021-03-04 |title=ととのうサウナの入り方 |url=https://www.yukaisoukai.com/chi/sauna-totonou/ |access-date=2024-07-25 |website=野天湯元 湯快爽快 ちがさき |language=ja}}</ref><ref>{{Cite web |title=サウナよりもととのう？ 本物の温泉好きがやみつきになる入浴法 （高橋一喜） - エキスパート |url=https://news.yahoo.co.jp/expert/articles/1a17f4a175fb01536ba3ecfd83d6070fc1bb299a |access-date=2024-07-25 |website=Yahoo!ニュース |language=ja}}</ref>

==Selected ''onsen''==
{{main|List of hot springs in Japan}}
{{cleanup list|section|date=February 2019}}
 [[File:Tsurunoyu Hotspring in Akita Pref Japan 001.JPG|thumb|Old Tsuru-no-yu Bathhouse in Nyūtō Onsen area, Akita]]
[[File:Tsurunoyu onsen rotenburo2.JPG|thumb|Winter bathing at Tsuru-no-yu roten-buro in Nyūtō, Akita]]
[[File:Kurokawa-onsen.jpg|thumb|Kurokawa Onsen {{not a typo|roten}}-buro in Kyushu]]
[[File:Jigokudani hotspring in Nagano Japan 001.jpg|thumb|[[Japanese macaque]]s enjoying a ''roten-buro'' open-air onsen at [[Jigokudani Monkey Park]]]]
[[File:Yumura onsen11s1920.jpg|thumb|Yumura-onsen's hot-spring resort and forests in [[Shin'onsen, Hyōgo]]]]
[[File:Dogo Hot Spring2(Matsuyama City).JPG|thumb|[[Dōgo Onsen]] hot springs (main building) in Matsuyama, Ehime]]
[[File:Ginzan Onsen 2019 no.3.png|thumb|[[Ginzan Onsen]] in [[Obanazawa, Yamagata]]]]
[[File:Yubatake (14308957671).jpg|thumb|[[Kusatsu, Gunma|Kusatsu Onsen]]]]
[[File:こちらは本日の黒玉子の色具合です (2305057549).jpg|right|thumb|[[Onsen tamago]] (black egg) [[Miyanoshita Onsen]]]]
<!-- PLEASE RESPECT ALPHABETICAL ORDER-->
* [[Akagi, Gunma]]
* [[Akayu, Yamagata]]
* [[Arima Onsen]], [[Kobe]], Hyōgo
* [[Asamushi Onsen]], [[Aomori Prefecture]]
* [[Aso, Kumamoto]], a famous onsen area alongside [[Mount Aso]], an active volcano
* [[Atami Onsen]], [[Atami]], Shizuoka, major onsen resort town near Tokyo
* [[Awara Onsen]], Awara, [[Fukui Prefecture]]
* [[Awazu Onsen]], [[Komatsu, Ishikawa]]
* [[Beppu Onsen]], [[Beppu]], Ōita Prefecture, famous for its multi-coloured springs
* {{Interlanguage link|Dake Onsen|ja|3=岳温泉}}, [[Nihonmatsu, Fukushima]]
* [[Dōgo Onsen]], [[Ehime Prefecture]]
* [[Funaoka Onsen]], [[Kyoto]]
* {{Interlanguage link|Gero Onsen|ja|3=下呂温泉}}, [[Gero, Gifu]], famous for its free open bath on riverbank of [[Hida River]]
* [[Geto Onsen]], [[Iwate Prefecture]]
* [[Ginzan Onsen]], Obanazawa, Yamagata
* [[Hakone]], [[Kanagawa Prefecture|Kanagawa]], famous onsen resort town near Tokyo
* [[Hanamaki, Iwate]]
* {{Interlanguage link|Hirayu Onsen|ja|3=平湯温泉}}, Takayama, Gifu
* {{Interlanguage link|Hokkawa Onsen|ja|3=北川温泉 (静岡県)}}, Shizuoka
* [[Ibusuki Onsen]], [[Kagoshima Prefecture]]
* [[Iizaka Onsen]], Fukushima
* {{Interlanguage link|Ikaho Onsen|ja|3=伊香保温泉}}, [[Ikaho]], Gunma
* [[Itō, Shizuoka]]
* [[Iwaki Yumoto Onsen]], [[Fukushima Prefecture]]
* [[Iwamuro, Niigata]], famous for onsen since the [[Edo period]]
* [[Jigokudani Monkey Park|Jigokudani]], [[Nagano Prefecture]]
* {{Interlanguage link|Jōzankei Onsen|ja|3=定山渓温泉}}, Hokkaido
* {{Interlanguage link|Kaike Onsen|ja|3=皆生温泉}}, [[Yonago]], Tottori
* {{Interlanguage link|Kakeyu Onsen|ja|3=鹿教湯温泉}}, Nagano
* {{Interlanguage link|Kanzanji Onsen|ja|3=舘山寺温泉}}, Shizuoka
* {{Interlanguage link|Katayamazu Onsen|ja|3=片山津温泉}}, [[Kaga, Ishikawa]]
* {{Interlanguage link|Kawayu Onsen|ja|3=川湯温泉 (和歌山県)}}, [[Tanabe, Wakayama]]
* [[Kindaichi Onsen]], Iwate
* [[Kinosaki, Hyōgo]]
* [[Kinugawa Onsen]], Tochigi
* [[Kusatsu, Gunma|Kusatsu Onsen]], Gunma Prefecture
* {{Interlanguage link|Misasa Onsen|ja|3=三朝温泉}}, [[Misasa]], [[Tottori Prefecture]]
* [[Nagaragawa Onsen]], [[Gifu, Gifu]]
* [[Nanki-Katsuura Onsen]], [[Nachikatsuura, Wakayama]]
* [[Nanki-Shirahama Onsen]], [[Shirahama, Wakayama|Shirahama]], [[Wakayama Prefecture]]
* [[Naoshima]], [[Kagawa Prefecture]]
* [[Naruko, Miyagi|Naruko]], [[Miyagi Prefecture|Miyagi]]
* [[Noboribetsu, Hokkaido|Noboribetsu]], Hokkaido
* [[Nuruyu Onsen]], [[Kumamoto Prefecture]]
* [[Nyūtō Onsen]], [[Akita Prefecture]]
* [[Obama Onsen]], [[Nagasaki Prefecture]], the hottest Japanese hot spring ({{convert|105|C|abbr=on|disp=or}})
* {{Interlanguage link|Onneyu Onsen|ja|3=温根湯温泉}}, Hokkaido
* [[Ōfuka Onsen]], Akita
* [[Ryujin Onsen]], [[Tanabe, Wakayama]], one of Japan's famous three beautifying onsen
* [[Sabakoyu Onsen]], [[Fukushima Prefecture]], the oldest community onsen in Japan
* [[Sakunami Onsen]], Miyagi
* [[Nakanojō, Gunma|Sawatari]], Gunma Prefecture
* {{Interlanguage link|Senami Onsen|ja|3=瀬波温泉}}, [[Niigata Prefecture]]
* [[Shima Onsen]], Gunma Prefecture
* [[Shimabara, Nagasaki]]
* {{Interlanguage link|Shimobe Onsen|ja|3=下部温泉}}, [[Yamanashi Prefecture]]
* {{Interlanguage link|Shiobara Onsen|ja|3=塩原温泉郷}}, [[Tochigi Prefecture]]
* [[Shuzenji Onsen]], Shizuoka Prefecture
* {{Interlanguage link|Sōunkyo Onsen|ja|3=層雲峡温泉}}, Hokkaido
* [[Sukayu Onsen]], Aomori Prefecture
* {{Interlanguage link|Sumatakyō Onsen|ja|3=寸又峡温泉}}, Shizuoka Prefecture
* [[Suwa, Nagano|Suwa]], Nagano Prefecture
* [[Takanoyu Onsen]], Akita Prefecture
* [[Takaragawa]], Gunma, one of the largest outdoor mixed baths in Japan
* [[Takarazuka, Hyōgo]]
* [[Tara, Saga]]
* [[Tōyako, Hokkaidō]]
* {{Interlanguage link|Tsubame Onsen|ja|3=燕温泉}}, Niigata - famous for its free open mixed onsen
* [[Tsuchiyu Onsen]], Fukushima Prefecture
* {{Interlanguage link|Tsukioka Onsen, Niigata|ja|3=月岡温泉}}, Niigata Prefecture
* {{Interlanguage link|Tsurumaki Onsen|ja|3=鶴巻温泉}}, Kanagawa
* [[Unazuki Onsen]], Kurobe, [[Toyama Prefecture]]
* [[Wakura Onsen]], Nanao, [[Ishikawa Prefecture]]
* [[Yamanaka Onsen]], [[Kaga, Ishikawa]]
* [[Yamashiro Onsen]], [[Kaga, Ishikawa]]
* {{Interlanguage link|Yubara Onsen|ja|3=湯原温泉}}, [[Okayama Prefecture]], one of the largest mixed baths at the foot of Yubara dam
* {{Interlanguage link|Yudanaka Onsen|ja|3=湯田中渋温泉郷}}, Nagano Prefecture
* [[Yufuin]], [[Ōita Prefecture]]
* [[Yugawara]], Kanagawa Prefecture
* [[Yumura Onsen (Hyogo)|Yumura Onsen]], ([[Shin'onsen, Hyōgo]])
* [[Yunogo Onsen]], Okayama Prefecture
* [[Yunokawa Onsen (Hokkaidō)|Yunokawa Onsen]], Hokkaido
* [[Yunomine Onsen]], [[Tanabe, Wakayama]], site of the UNESCO World Heritage Tsuboyu bath
* [[Yuzawa, Niigata]]
* [[Zaō Onsen]], [[Yamagata Prefecture]]

==See also==
* [[Ashiyu]]
* [[Balneotherapy]]
* [[Furo]]
* [[List of hot springs in Japan]]
* [[Public bathing]]
* [[Sauna]]
* [[Taiwanese hot springs]]
* [[Three Ancient Springs]]
* [[Victorian Turkish baths]]
* [[:ja:Portal:温泉|Onsen portal]] at the Japanese Wikipedia {{in lang|ja}}

==Notes==
{{notelist}}

==References==
{{reflist|30em}}

==Further reading==
* Hotta, Anne, and Yoko Ishiguro. ''A Guide to Japanese Hot Springs''. New York: Kodansha America, 1986. {{ISBN|0-87011-720-3}}.
* Fujinami, Kōichi. ''Hot Springs in Japan''. Tokyo: Board of Tourist Industry, [[Japanese Government Railways]]; Maruzen Company, Ltd., 1936.
* Neff, Robert. ''Japan's Hidden Hot Springs''. Rutland, Vermont: Charles E. Tuttle, 1995. {{ISBN|0-8048-1949-1}}.
* Seki, Akihiko, and Elizabeth Heilman Brooke. ''The Japanese Spa: A Guide to Japan's Finest Ryokan and Onsen''. Boston: Tuttle Publishing, 2005. {{ISBN|0-8048-3671-X}}. Reprinted as ''Ryokan: Japan's Finest Spas and Inns'', 2007. {{ISBN|0-8048-3839-9}}.

==External links==
{{Commons category|Hot springs of Japan}}
{{Wikivoyage|Public baths in Japan}}
* [http://www.onsentipster.com Onsen Tipster] A database of genuine onsen in Japan
* [http://www.sentoguide.info Sento Guide] Guide to public baths in Japan
* [http://www.onsenjapan.net/ OnsenJapan.net] Interactive Google map with easy-to-read icons, pictures, and reviews
* [http://www.secret-japan.com/onsen/ Secret Onsen] a database with more than 125 onsen all around Japan
* [http://japan-onsen.com/japan_onsen.htm Japan Onsen] A mountain onsen guide of the Japan Alps
* [https://japanbased.com/onsen-guide Japanbased Onsen guide] A guide on how to onsen in Japan

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[[Category:Bathing in Japan]]
[[Category:Hot springs of Japan| ]]
[[Category:Public baths in Japan]]
[[Category:Articles containing video clips]]