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{{Short description|1922 pact by the Allies of WWI}}
{{Infobox treaty
| name = Washington Naval Treaty
| long_name = Limitation of Naval Armament
| image = Washington Naval Treaty.jpg
| image_size = 
| alt = 
| caption = Signing of the Washington Naval Treaty (1922)
| type = [[Arms control]]
| context = [[World War I]]
| date_signed = {{Start date|1922|2|6}}
| location_signed = [[Memorial Continental Hall]], [[Washington, D.C.]]
| date_sealed = 
| date_effective = {{Start date|1923|8|17}}
| date_expiration = {{End date|1936|12|31}}
| mediators = 
| negotiators = {{plainlist|
*{{flagicon|United States|1912}} [[Charles Evans Hughes]]
*{{flagicon|United Kingdom}} [[Arthur Balfour]]
*{{flagicon|French Third Republic}} [[Albert Sarraut]]
*{{flagicon|Kingdom of Italy}} [[Carlo Schanzer]]
*{{flagicon|Empire of Japan}} [[Katō Tomosaburō]]}}
| signatories = {{plainlist|
*{{flagicon|United States|1912}} [[Warren G. Harding]]
*{{flagicon|British Empire}} [[George V]]
*{{flagicon|French Third Republic}} [[Alexandre Millerand]]
*{{flagicon|Kingdom of Italy}} [[Victor Emmanuel III of Italy|Victor Emmanuel III]]
*{{flagicon|Empire of Japan}} [[Emperor Taishō|Yoshihito]]}}
| parties = {{plainlist|
*{{flag|United States|1912}}
*{{flag|British Empire}}
*{{nbsp}}{{nbsp}}{{flagcountry|United Kingdom of Great Britain and Ireland}}
*{{nbsp}}{{nbsp}}{{flag|Canada|1907}}
*{{nbsp}}{{nbsp}}{{flag|Australia|1907}}
*{{nbsp}}{{nbsp}}{{flagcountry|Union of South Africa|1912}}
*{{nbsp}}{{nbsp}}{{flagcountry|Dominion of New Zealand}}
*{{nbsp}}{{nbsp}}{{flagcountry|British India|variant=Viceroy}}
*{{flag|French Third Republic}}
*{{flag|Kingdom of Italy}}
*{{flag|Empire of Japan}}}}
| ratifiers = 
| depositor = [[League of Nations]]
| citations = [https://treaties.un.org/doc/Publication/UNTS/LON/Volume%2025/v25.pdf 25 L.N.T.S. 202]
| languages = * [[French language|French]]
* [[English language|English]]
| wikisource = Washington Naval Treaty, 1922
}}

The '''Washington Naval Treaty''', also known as the '''Five-Power Treaty''', was signed during 1922 among the major [[Allies of World War I|Allies]] of [[World War I]], which agreed to prevent an [[arms race]] by limiting [[Navy|naval]] construction. It was negotiated at the [[Washington Naval Conference]] in [[Washington, D.C.]], from November 1921 to February 1922 and signed by the governments of the [[British Empire]] (including the United Kingdom, Canada, Australia, New Zealand, South Africa and India), [[United States]], [[French Third Republic|France]], [[Kingdom of Italy|Italy]], and [[Empire of Japan|Japan]]. It limited the construction of [[battleship]]s, [[battlecruiser]]s and [[aircraft carrier]]s by the signatories. The numbers of other categories of warships, including [[cruiser]]s, [[destroyer]]s, and [[submarine]]s, were not limited by the treaty, but those ships were limited to 10,000 tons [[displacement (ship)|displacement]] each.

The treaty was finalized on February 6, 1922.  Ratifications of it were exchanged in Washington on August 17, 1923, and it was registered in the ''[[League of Nations Treaty Series]]'' on April 16, 1924.<ref>Feb. 6, 1922, 25 L.N.T.S. 202.</ref>

Later conferences on naval arms limitation sought additional limitations of warship building. The terms of the Washington Naval Treaty were modified by the [[London Naval Treaty]] of 1930 and the [[Second London Naval Treaty]] of 1936. By the mid-1930s, Japan and Italy had renounced the treaties, while [[Nazi Germany|Germany]] renounced the [[Treaty of Versailles]] which had limited its navy. Naval arms limitation became increasingly difficult for the other signatories.

==Background==
Immediately after World War I, Britain still had the world's largest and most powerful navy, followed by the United States and, more distantly, by Japan, France and Italy.{{cn | reason = measured how? tonnage? firepower?|date=July 2024}} The British [[Royal Navy]] interned the defeated [[German High Seas Fleet]] in November 1918. The [[Allies of World War I|Allies]] had differing opinions concerning the final disposition of the [[Imperial German Navy]], with the French and Italians wanting the German fleet divided between the victorious powers and the Americans and British wanting the ships destroyed. The negotiations became mostly moot after the German crews [[scuttling of the German fleet at Scapa Flow|scuttled most of their ships]] on June 21, 1919.

News of the scuttling angered the French and the Italians, with the French particularly unimpressed with British explanations that the fleet guarding the Germans had then been away on exercises. Nevertheless, the British joined their allies in condemning the German actions, and no credible evidence emerged to suggest that the British had collaborated with the Germans with respect to the scuttling. The [[Treaty of Versailles]], signed a week later on June 28, 1919, imposed strict limits on the sizes and numbers of warships which the newly-installed [[Weimar Republic|German government]] had the right to build and maintain.<ref name="Versailles">{{cite book | title=Treaty of Versailles | chapter=Part V. Military, Naval and Air Clauses | chapter-url=https://en.wikisource.org/wiki/Treaty_of_Versailles/Part_V#Article_181 | publisher=Wikisource |date=June 28, 1919 |access-date=24 August 2023 |url-status=live |archive-url=https://web.archive.org/web/20230824071321/https://en.wikisource.org/wiki/Treaty_of_Versailles/Part_V#Article_181 | archive-date=24 August 2023 }}</ref>

The Americans, British, French, Italians, and Japanese had been allies during World War I, but with the German threat seemingly finished, a naval [[arms race]] between the allies seemed likely.{{Sfn | Marriott | 2005 | p = 9}} US President [[Woodrow Wilson]]'s administration had already announced successive plans for the expansion of the [[US Navy]] from 1916 to 1919 that would have resulted in a massive fleet of 50 modern battleships.{{Sfn | Potter | 1981 | p = 232}}

In response, the [[Japanese Diet]] in 1920 finally authorised construction of warships to enable the [[Imperial Japanese Navy]] to attain its goal of an [[eight-eight fleet|"eight-eight" fleet programme]], with eight modern battleships and eight battlecruisers. The Japanese started work on four battleships and four battlecruisers, all of which were much larger and more powerful than those of the classes that they were replacing.{{Sfn | Evans | Peattie | 1997 | p = 174}}

The 1921 [[History of the Royal Navy (after 1707)|British Naval Estimates]] planned four battleships and four battlecruisers, with another four battleships to follow the subsequent year.{{Sfn | Marriott | 2005 | p = 9}}

The new arms race was unwelcome to the American public. The [[US Congress]] disapproved of Wilson's 1919 naval expansion plan, and the [[1920 United States presidential election|1920 presidential election]] campaign resulted in politicians in Washington resuming the [[United States non-interventionism|non-interventionism]] of the prewar era, with little enthusiasm for continued naval expansion.{{Sfn | Potter | 1981 | p = 233}} Britain also could ill afford the exorbitant cost of capital ships.{{Sfn | Kennedy | 1983 | p = 274}}

In late 1921, the US became aware that Britain was planning a conference to discuss the strategic situation in the Pacific and [[Far East]] regions. To forestall the British plan and to satisfy domestic demands for a global [[disarmament]] conference, [[Warren Harding]]'s administration called the Washington Naval Conference in November 1921.{{Sfn | Marriott | 2005 | p = 10}}

The Conference agreed to the Five-Power Naval Treaty as well as a [[Four-Power Treaty]] on Japan and a [[Nine-Power Treaty]] on China.<ref name="Brittanica">{{cite web |title=Washington Conference {{!}} 1921–1922 | url=https://www.britannica.com/event/Washington-Conference-1921-1922 | website=Encyclopedia Britannica | access-date=6 April 2019 }}</ref>

==Negotiations==
At the first plenary session held November 21, 1921, US Secretary of State [[Charles Evans Hughes]] presented his country's proposals. Hughes provided a dramatic beginning for the conference by stating with resolve: "The way to disarm is to disarm".{{Sfn|Jones|2001|p=119}} The ambitious slogan received enthusiastic public endorsement and likely abbreviated the conference while helping ensure his proposals were largely adopted. He subsequently proposed the following:
* A ten-year pause or "holiday" of the construction of [[capital ship]]s (battleships and battlecruisers), including the immediate suspension of all building of capital ships.
* The scrapping of existing or planned capital ships to give a 5:5:3:1.67:1.67 ratio of tonnage with respect to Britain, the United States, Japan, France and Italy respectively.
* Ongoing limits of both capital ship tonnage and the tonnage of secondary vessels with the 5:5:3 ratio.

===Capital ships===
The proposals for capital ships were largely accepted by the British delegation. However, they were controversial with the British public. Britain could no longer have adequate fleets in the [[North Sea]], the [[Mediterranean Fleet|Mediterranean]] and the [[Far East]] simultaneously, which provoked outrage from parts of the Royal Navy.{{citation needed|date=February 2019}}

Nevertheless, there was huge demand for the British to agree to the limits and reductions: the risk of war with the Americans was increasingly regarded as merely theoretical as there were very few policy differences between the two [[Anglosphere|Anglophone]] powers; continued naval spending was unpopular in Britain throughout the empire; and Britain was implementing major budget reductions due to the [[post–World War I recession]].{{Sfn | Kennedy | 1983 | pp = 275–276}}

The Japanese delegation was divided. Japanese naval doctrine required the maintenance of a fleet 70% the size of that of the United States, which was felt to be the minimum necessary to defeat the Americans in any subsequent war. The Japanese envisaged two separate engagements, first with the [[U.S. Pacific Fleet]] and then with the [[U.S. Atlantic Fleet]]. It calculated that a 7:5 ratio in the first battle would produce enough of a margin of victory to be able to win the subsequent engagement and so a 3:5 ratio was unacceptable because a 3:5 total fleet size ratio would imply a 6:5 ratio in the first battle. Nevertheless, the director of the delegation, [[Katō Tomosaburō]], preferred to accept the latter to the prospect of an arms race with the United States, as the relative industrial strength of the two nations would cause Japan to lose such an arms race and possibly suffer an economic crisis. At the beginning of the negotiations, the Japanese had only 55% of the capital ships and 18% of the GDP of the Americans.{{citation needed|date=February 2019}}

[[File:Japanese aircraft carrier Akagi 1925.jpg|thumb|''[[Japanese aircraft carrier Akagi|Akagi]]'' (Japanese ship originally planned as a battlecruiser but converted during construction to an aircraft carrier) in April 1925]]

His opinion was opposed strongly by [[Kanji Kato|Katō Kanji]], the president of the Naval Staff College, who acted as his chief naval aide at the delegation and represented the influential "big navy" opinion that Japan had to prepare as thoroughly as possible for an inevitable conflict against the United States, which could build more warships because of its superior industrial might.<ref>{{Cite web |title=ワシントン会議から１０年、こんなに日本が不利になるとは {{!}} 渡部昇一 {{!}} テンミニッツTV |url=https://10mtv.jp/pc/content/detail.php?movie_id=937 |access-date=2024-11-06 |website=10mtv.jp |language=ja}}</ref>

Katō Tomosaburō was finally able to persuade the Japanese high command to accept the Hughes proposals, but the treaty was for years a source of controversy in the navy.{{Sfn | Evans | Peattie | 1997 | pp = 193–196}}

The French delegation initially responded negatively to the idea of reducing their capital ships' tonnage to 175,000 tons and demanded 350,000, slightly above the Japanese limit. In the end, concessions regarding cruisers and submarines helped persuade the French to agree to the limit on capital ships.{{Sfn | Marriott | 2005 | p = 11}}

Another issue that was considered critical by the French representatives was the Italian request of substantial parity, which was considered to be unsubstantiated; however, pressure from the American and the British delegations caused the French to accept it. That was considered a great success by the Italian government, but parity would never actually be attained.<ref>{{cite book|last1=Giorgerini|first1=Giorgio|title=Uomini sul fondo: storia del sommergibilismo italiano dalle origini a oggi|date=2002|publisher=Mondadori|location=Milano|isbn=978-88-04-50537-2|pages=84–85}}</ref>

There was much discussion about the inclusion or exclusion of individual warships. In particular, the Japanese delegation was keen to retain their newest battleship [[Japanese battleship Mutsu|''Mutsu'']], which had been funded with great public enthusiasm, including donations from schoolchildren.{{Sfn | Evans | Peattie | 1997 | p = 197}} That resulted in provisions to allow the Americans and the British to construct equivalent ships.{{citation needed|date=February 2019}}

===Cruisers and destroyers===
[[File:HMS Hawkins quayside.jpg|thumb|{{HMS|Hawkins|D86|6}}, [[lead ship]] for [[Hawkins-class cruiser|her class]] of heavy cruisers alongside a [[quay]], probably during the interwar period]]

Hughes proposed to limit secondary ships ([[cruiser]]s and [[destroyer]]s) in the same proportions as capital ships. However, that was unacceptable to both the British and the French. The British counterproposal, in which the British would be entitled to 450,000 tons of cruisers in consideration of its [[British Empire|imperial commitments]] but the United States and Japan to only 300,000 and 250,000 respectively, proved equally contentious. Thus, the idea of limiting total cruiser tonnage or numbers was rejected entirely.{{Sfn | Marriott | 2005 | p = 11}}

Instead, the British suggested a qualitative limit of future cruiser construction. The limit proposed, of a 10,000 ton maximum displacement and 8-inch calibre guns, was intended to allow the British to retain the [[Hawkins class cruiser|''Hawkins'' class]], then being constructed. That coincided with the American requirements for cruisers for Pacific Ocean operations and also with Japanese plans for the [[Furutaka class cruiser|''Furutaka'' class]]. The suggestion was adopted with little debate.{{Sfn | Marriott | 2005 | p = 11}}

===Submarines===
A major British demand during the negotiations was the complete abolition of the submarine, which had proved so effective against them [[Submarine warfare#World War I|in the war]]. That proved impossible, particularly as a result of French opposition, which demanded an allowance of 90,000 tons of submarines,{{Sfn | Marriott | 2005 | pp = 10–11}} and the conference ended without an agreement to restrict submarines.<ref>{{Cite journal |doi = 10.1017/S0010417500005879|title = Open Diplomacy at the Washington Conference of 1921–2: The British and French Experience|journal = Comparative Studies in Society and History|volume = 12|issue = 3|pages = 297–319|year = 1970|last1 = Birn|first1 = Donald S.| s2cid=143583522 }}</ref>

===Pacific bases===
Article XIX of the treaty also prohibited the British, the Japanese and the Americans from constructing any new fortifications or naval bases in the [[Pacific Ocean]] region. Existing fortifications in [[Singapore]], the [[Philippines]] and [[Hawaii]] could remain. That was a significant victory for Japan, as newly-fortified British or American bases would be a serious problem for the Japanese in the event of any future war. That provision of the treaty essentially guaranteed that Japan would be the dominant power in the [[Western Pacific Ocean]] and was crucial in gaining Japanese acceptance of the limits on capital ship construction.{{Sfn | Evans | Peattie | 1997 | p = 199}}

==Terms==
{|class="wikitable" align="right" style="text-align:center"
| colspan=3 | '''Tonnage limitations'''
|-
! Country !! Capital ships !! Aircraft carriers
|-
| British Empire || 525,000 [[long ton|tons]]<br />(533,000 [[tonnes]]) || 135,000 tons<br />(137,000 tonnes)
|-
| United States || 525,000 tons<br />(533,000 tonnes) || 135,000 tons<br />(137,000 tonnes)
|-
| Empire of Japan || 315,000 tons<br />(320,000 tonnes) || 81,000 tons<br />(82,000 tonnes)
|-
| France || 175,000 tons<br />(178,000 tonnes) || 60,000 tons<br />(61,000 tonnes)
|-
| Italy || 175,000 tons<br />(178,000 tonnes) || 60,000 tons<br />(61,000 tonnes)
|}

The treaty strictly limited both the tonnage and construction of capital ships and aircraft carriers and included limits of the size of individual ships.

The tonnage limits defined by Articles IV and VII (tabulated) gave a strength ratio of approximately 5:5:3:1.75:1.75 for the UK, the United States, Japan, Italy, and France, respectively.<ref>25 L.N.T.S. at 205–06.</ref>

The qualitative limits of each type of ship were as follows:
*Capital ships (battleships and battlecruisers) were limited to 35,000 tons [[standard displacement]] and guns of no larger than 16-inch calibre. (Articles V and VI)
*Aircraft carriers were limited to 27,000 tons and could carry no more than 10 heavy guns, of a maximum calibre of 8 inches. However, each signatory was allowed to use two existing capital ship hulls for aircraft carriers, with a displacement limit of 33,000 tons each (Articles IX and X). For the purposes of the treaty, an aircraft carrier was defined as a warship displacing more than 10,000 tons constructed exclusively for launching and landing aircraft. Carriers lighter than 10,000 tons, therefore, did not count towards the tonnage limits (Article XX, part 4). Moreover, all aircraft carriers then in service or building (''[[HMS Argus (I49)|Argus]]'', ''[[HMS Eagle (1918)|Eagle]]'', ''[[HMS Furious (47)|Furious]]'', ''[[HMS Hermes (95)|Hermes]]'', ''[[USS Langley (CV-1)|Langley]]'' and ''[[Japanese aircraft carrier Hōshō|Hōshō]]'') were declared "experimental" and could be replaced without regard to their age, unlike other capital ships (Article VIII).
*All other warships were limited to a maximum displacement of 10,000 tons and a maximum gun calibre of 8 inches (Articles XI and XII).

The treaty also detailed by Chapter II the individual ships to be retained by each navy, including the allowance for the United States to complete two further ships of the [[Colorado-class battleship|''Colorado'' class]] and for the UK to complete two new ships in accordance with the treaty limits (the [[Nelson-class battleship|''Nelson'' class]]).

Chapter II, part 2, detailed what was to be done to render a ship ineffective for military use. In addition to sinking or scrapping, a limited number of ships could be converted as target ships or training vessels if their armament, armour and other combat-essential parts were removed completely. Some could also be converted into aircraft carriers.

Part 3, Section II specified the ships to be scrapped to comply with the treaty and when the remaining ships could be replaced. In all, the United States had to scrap 30 existing or planned capital ships, Britain 23 and Japan 17.

==Effects==
[[File:Battleship building scatter graph 1905 onwards.png|thumb|350px|The treaty arrested the continuing upward trend of battleship size and halted new construction entirely for more than a decade.]]
The treaty marked the end of a long period of increases of battleship construction. Many ships that were being constructed were scrapped or converted into [[aircraft carriers]]. Treaty limits were respected and then extended by the London Naval Treaty of 1930. It was not until the mid-1930s that navies began to build battleships once again, and the power and the size of new battleships began to increase once again. The Second London Naval Treaty of 1936 sought to extend the Washington Treaty limits until 1942, but the absence of Japan or Italy made it largely ineffective.

There were fewer effects on cruiser building. The treaty specified 10,000 tons and 8-inch guns as the maximum size of a cruiser, but that was also the minimum size cruiser that any navy was willing to build. The treaty began a building competition of 8-inch, 10,000-ton "[[treaty cruiser]]s", which gave further cause for concern.{{Sfn | Marriott | 2005 | p = 3}} Subsequent naval treaties sought to address that by limiting cruiser, destroyer and submarine tonnage.

Unofficial effects of the treaty included the end of the [[Anglo-Japanese Alliance]]. Although it was not part of the Washington Treaty in any way, the American delegates had made it clear that they would not agree to the treaty unless the British ended their alliance with the Japanese.{{Sfn | Howarth | 1983 | p = 167}} The [[1921 Imperial Conference]] earlier in the year had already decided not to renew the Alliance.<ref>{{Citation|last=Nish |first=Ian H. |title=Alliance in Decline: A Study in Anglo-Japanese Relations 1908–23 |location=London |publisher=The Athlone Press |date=1972 |page=334 |isbn=0-485-13133-1 }}</ref>

==Violations==
In 1935, the [[French Navy]] laid down the battleship {{ship|French battleship|Richelieu||2}}; combined with the two {{Sclass|Dunkerque|battleship|1}}s also under construction, which placed the total tonnage over the 70,000-ton limit on new French battleships until the expiration of the treaty. The keel laying of {{ship|French battleship|Jean Bart|1940|2}} in December 1936, albeit less than three weeks before the treaty expired, increased the magnitude of France's violation by another 35,000 tons. The French government dismissed British objections to the violations by pointing out that Britain had signed the [[Anglo-German Naval Agreement]] in 1935, which unilaterally dismantled the naval disarmament clauses of the Treaty of Versailles. German naval rearmament threatened France, and according to the French perspective, if Britain freely violated treaty obligations, France would similarly not be constrained.{{sfn|Jordan|Dumas|2009|pp=98–99, 152}}

Italy repeatedly violated the displacement limits on individual ships but attempted to remain within the 10,000-ton limit for the {{Sclass|Trento|cruiser|1}}s built in the mid-1920s. However, by the {{Sclass|Zara|cruiser|1}}s in the late 1920s and early 1930s, it had abandoned all pretense and built ships that topped {{cvt|11000|LT}} by a wide margin. The violations continued with the {{Sclass|Littorio|battleship|1}}s of the mid-1930s, which had a standard displacement in excess of {{cvt|40000|LT}}. The [[Italian Navy]] nevertheless misrepresented the displacement of the vessels as being within the limits imposed by the treaty.{{sfn|Gardiner|Chesneau|1980|pp=290–292}}

===Loopholes===
Several powers attempted to exploit loopholes in the treaty, though it is arguable whether these were technically violations of the treaty. 

The Japanese light aircraft carrier [[Japanese_aircraft_carrier_Ryūjō|''Ryūjō'']] was an effort to exploit the definition of an aircraft carrier as being "a vessel of war with a displacement in excess of 10,000 tons", by building a carrier of less than 10,000 tons, which would not be restricted by the treaty. However, the ship was not large enough to be fully capable, and was later expanded to be over 10,000 tons total. This loophole was closed by the London Naval Treaty, so no ships besides ''Ryūjō'' ever attempted this approach. 

The American conversions of {{USS|Lexington|CV-2|6}} and {{USS|Saratoga|CV-3|6}} from battlecruisers to carriers was supposed to be done with a tonnage of no more than 33,000 tons, as conversions. However, the ships were overweight, so the US took advantage of the rules for reconstructing ships to add an additional 3,000 tons of weight limit to them for anti-air/anti-submarine defenses, arguing that they were being "reconstructed" as they were being constructed. No other power ever attempted to make this argument. 

The British [[Nelson-class_battleship|''Nelson'' class]] took advantage of the fact that the definition of tonnage excluded fuel and reserve boiler feed water. Anti-torpedo defense systems were most effective with liquid layers to absorb the shock of a torpedo strike, however liquids are quite heavy. By building their torpedo defenses such that the water within was usable as reserve boiler feed water, this weight was not counted towards the displacement limit of the ships, thus allowing stronger torpedo defenses than would otherwise have been practical.

==Japanese denunciation==
[[File:Japanese denonciation of the Washington Treaty 29 December 1934.jpg|thumb|Japanese denunciation of the Washington Naval Treaty, December 29, 1934]]
The naval treaty had a profound effect on the Japanese. With superior American and British industrial power, a long war would very likely end in a Japanese defeat. Thus, gaining strategic parity was not economically possible.{{Sfn |Paine| 2017 | p = 104-105 }}

Many Japanese considered the 5:5:3 ratio of ships as another snub by the West, but it can be argued that the Japanese had a greater [[force concentration]] than the US Navy or the Royal Navy. The terms also contributed to controversy in high ranks of the Imperial Japanese Navy between the [[Treaty Faction]] officers and their [[Fleet Faction]] opponents, who were also allied with the ultranationalists of the Japanese army and other parts of the Japanese government. For the Treaty Faction, the treaty was one of the factors that had contributed to the deterioration of the relationship between the American and the Japanese governments.

Some have also argued that the treaty was one major factor in prompting Japanese expansionism by the Fleet Faction in the early 1930s. The perception of unfairness resulted in Japan's renunciation of the [[Second London Naval Treaty]] in 1936.

[[File:Yamato during Trial Service.jpg|thumb|right|''[[Japanese battleship Yamato|Yamato]]'' during sea trials, October 1941. It displaced 72,800 tonnes at full load.]]

[[Isoroku Yamamoto]], who later masterminded the [[attack on Pearl Harbor|attack of Pearl Harbor]], argued that Japan should remain in the treaty while [[Chūichi Nagumo]] argued against it.
Yamamoto's opinion was more complex, however, in that he believed the United States could outproduce Japan by a greater factor than the 5:3 ratio because of the huge American production advantage of which he had expert knowledge since he had served with the Japanese embassy in Washington. After the signing of the treaty, he commented, "Anyone who has seen the auto factories in [[Detroit]] and the oil-fields in [[Texas]] knows that Japan lacks the power for a naval race with America." He later added, "The ratio works very well for Japan – it is a treaty to restrict the other parties."{{Sfn | Howarth | 1983 | p = 152}} He believed that other methods than a spree of construction would be needed to even the odds, which may have contributed to his advocacy of the plan to attack Pearl Harbor.

On December 29, 1934, the Japanese government gave formal notice that it intended to terminate the treaty. Its provisions remained in force formally until the end of 1936 and were not renewed.{{Sfn | Evans | Peattie | 1997 | p = 298}}

==Influences of cryptography==

What was unknown to the participants of the Conference was that the American "[[Black Chamber]]" (the Cypher Bureau, a US intelligence service), commanded by [[Herbert Yardley]], was spying on the delegations' communications with their home capitals. In particular, Japanese communications were deciphered thoroughly, and American negotiators were able to get the absolute minimum possible deal that the Japanese had indicated they would ever accept.{{Sfn | Duroselle | 1963 | p = 156}}

As the treaty was unpopular with much of the Imperial Japanese Navy and with the increasingly active and important ultranationalist groups, the value that the Japanese government accepted was the cause of much suspicion and accusation among Japanese politicians and naval officers.<ref>{{Cite journal |last=高光 |first=佳絵 |title=戦間期のグローバリゼーションをめぐる日本海軍と英米の対応 |url=https://hermes-ir.lib.hit-u.ac.jp/hermes/ir/re/10230/ronso1290100410.pdf |journal=一橋論叢 |volume=第129巻 |issue=第1号平|archive-url=https://web.archive.org/web/20250307195622/https://hermes-ir.lib.hit-u.ac.jp/hermes/ir/re/10230/ronso1290100410.pdf|archive-date=7 March 2025|url-status=dead}}</ref>

== See also ==

* [[Arms control]]

==References==
{{Reflist|2}}

==Sources==
* {{cite journal|last1=Baker|first1=A. D. III|year=1989 |title=Battlefleets and Diplomacy: Naval Disarmament Between the Two World Wars|journal=Warship International|volume=XXVI |issue=3 |pages=217–255 |issn=0043-0374}}
* {{Citation | last = Duroselle | first = Jean-Baptiste | title = From Wilson to Roosevelt: Foreign Policy of the United States, 1913-1945 | publisher = Harvard University Press | year = 1963 | isbn = 978-0-67432-650-7}}
* {{Citation | last1 = Evans | first1 = David | last2 = Peattie | first2 = Mark | title = Kaigun: Strategy, Tactics and Technology in the Imperial Japanese Navy, 1887–1941 | publisher = Naval Institute Press | place = Annapolis | year = 1997 | isbn = 978-0-87021-192-8 |name-list-style=amp}}.
* {{cite book|editor-last1=Gardiner|editor-first1=Robert|editor-last2=Chesneau|editor-first2=Roger|title=Conway's All the World's Fighting Ships 1922–1946|location=Annapolis|publisher=Naval Institute Press|year=1980|isbn=0-87021-913-8|name-list-style=amp}}
* {{Citation | last = Howarth | first = Stephen | title = The Fighting Ships of the Rising Sun | publisher = Atheneum | year = 1983 | isbn = 978-0-689-11402-1}}
* {{Citation | last = Jones | first = Howard | title = Crucible of power: a history of US foreign relations since 1897 | publisher = Rowman & Littlefield | year = 2001 | isbn = 978-0-8420-2918-6 | url-access = registration | url = https://archive.org/details/crucibleofpower00jone }}
* {{Citation | last = Jordan | first = John | title = Warships after Washington: The Development of Five Major Fleets 1922&ndash;1930 | publisher = Seaforth Publishing | year = 2011 | isbn = 978-1-84832-117-5 }}
* {{cite book|last1=Jordan|first1=John|last2=Dumas|first2=Robert|title=French Battleships 1922–1956|publisher=Seaforth Punblishing|isbn=978-1-84832-034-5|year=2009|location=Barnsley| name-list-style = amp}}
* {{Citation | last = Kaufman | first = Robert Gordon | title = Arms Control During the Pre-Nuclear Era: The United States and Naval Limitation Between the Two World Wars | publisher = Columbia University Press | place = New York | year = 1990 | isbn = 978-0-231-07136-9}}
* {{Citation | last = Kennedy | first = Paul | title = The Rise and Fall of British Naval Mastery | publisher = Macmillan | place = London | year = 1983 | isbn = 978-0-333-35094-2}}
* {{Citation | last = Marriott | first = Leo | title = Treaty Cruisers: The First International Warship Building Competition | publisher = Pen & Sword | place = Barnsley | year = 2005 | isbn = 978-1-84415-188-2}}
* {{Citation | last = Paine  | first = S.C.M. | title = The Japanese Empire: Grand Strategy from the Meiji Restoration to the Pacific War | publisher = Cambridge | place = Cambridge & New York | year = 2017 | isbn = 978-1-107-01195-3}}
* {{Citation | editor-last = Potter | editor-first = E | title = Sea Power: A Naval History | edition = 2nd | publisher = Naval Institute Press | place = Annapolis | year = 1981 | isbn = 978-0-87021-607-7}}
* [https://www.loc.gov/law/help/us-treaties/bevans/m-ust000002-0351.pdf Limitation of Naval Armament], treaty, 1922

==External links==
{{wikisource|Washington Naval Treaty, 1922}}
* {{Cite conference | url = http://www.ibiblio.org/pha/pre-war/1922/nav_lim.html | publisher = iBiblio | title = Conference on the Limitation of Armament | year = 1922 | type = full text}}: the Washington Naval Treaty.
* {{Cite journal | url = https://books.google.com/books?id=wN4DAAAAMBAJ&q=Popular+Science+1930+plane+%22Popular+Mechanics%22&pg=PA738 | title = The New Navies | journal = Popular Mechanics |date=May 1929 | pages = 738–48 | type = article}}: on warships provided for under the treaty.
* [https://web.archive.org/web/20110106203445/http://edsitement.neh.gov/lesson-plan/postwar-disillusionment-and-quest-peace-1921-1929 EDSITEment lesson Postwar Disillusionment and the Quest for Peace 1921–1929]
* [https://www.youtube.com/watch?v=amsMUo1Az00&ab_channel=Drachinifel In depth video discussion of the Washington Naval Treaty]
{{Interwar Naval Arms Limitation}}
{{Treaties of Japan}}
{{Authority control}}

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