Washington Naval Treaty

The Washington Naval Treaty, also known as the Five-Power Treaty, the Four-Power Treaty, and the Nine-Power Treaty, was a treaty signed during 1922 among the major nations that had won World War I, which agreed to prevent an arms race by limiting naval construction. It was negotiated at the Washington Naval Conference, held in Washington, D.C., from November 1921 to February 1922, and it was signed by the governments of the United Kingdom, the United States, France, Italy, and Japan. It limited the construction of battleships, battlecruisers and aircraft carriers by the signatories. The numbers of other categories of warships, including cruisers, destroyers and submarines, were not limited by the treaty, but those ships were limited to 10,000 tons displacement each.

The treaty was concluded on February 6, 1922. Ratifications of that treaty were exchanged in Washington on August 17, 1923, and it was registered in the League of Nations Treaty Series on April 16, 1924.[1]

Later naval arms limitation conferences sought additional limitations of warship building. The terms of the Washington 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 renounced the treaties, while Germany renounced the Treaty of Versailles which had limited its navy. Naval arms limitation became increasingly difficult for the other signatories.

Washington Naval Treaty
Limitation of Naval Armament
Washington Naval Treaty
Signing of the Washington Naval Treaty.
TypeArms control
ContextWorld War I
SignedFebruary 6, 1922
LocationMemorial Continental Hall, Washington, D.C.
EffectiveAugust 17, 1923
ExpirationDecember 31, 1936
Washington Naval Treaty, 1922 at Wikisource


Immediately after World War I, the United Kingdom had the world's largest and most powerful navy, followed by the United States and more distantly by Japan, France and Italy. The High Seas Fleet of defeated Germany had been interned by the British. The allies had differing opinions concerning the final disposition of the German fleet, with the French and Italians wanting the German fleet divided between the victorious powers and the Americans and British wanting the ships destroyed. These negotiations became mostly moot when the German crews scuttled most of their ships. News of the scuttling angered the French and Italians, with the French particularly unimpressed with British explanations that their fleet guarding the Germans had been away on exercises at the time. Nevertheless, the British joined their allies in condemning the German actions and no credible evidence emerged to suggest that the British had collaborated actively with the Germans with respect to the scuttling. The Treaty of Versailles, signed soon after the scuttling of the German High Seas Fleet, imposed strict limits on the size and number of warships that the newly-installed German government was allowed to build and maintain.

The US, UK, France, Italy, and Japan had been allied for World War I; but with the German threat seemingly finished, a naval arms race between the erstwhile allies seemed likely for the next few years.[2] 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.[3]

In response, the Japanese parliament finally authorized construction of warships to enable the Japanese Navy to attain its goal of an "eight-eight" fleet programme, with eight modern battleships and eight battlecruisers. The Japanese started work on four battleships and four battlecruisers, all much larger and more powerful than those of the classes preceding.[4]

The 1921 British Naval Estimates planned four battleships and four battlecruisers, with another four battleships to follow the subsequent year.[2]

The new arms race was unwelcome to the U.S. public. The United States Congress disapproved of Wilson's 1919 naval expansion plan, and during the 1920 presidential election campaign, politics resumed the non-interventionalism of the prewar era, with little enthusiasm for continued naval expansion.[5] Britain also could ill afford any resumption of battleship construction, given the exorbitant cost.[6]

During late 1921, the USA government became aware that Britain was planning a conference to discuss the strategic situation in the Pacific and Far East regions. To forestall the conference and satisfy domestic demands for a global disarmament conference, the Harding administration called the Washington Naval Conference during November 1921.[7]


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".[8] 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 ships (battleships and battlecruisers), including the immediate suspension of all building of capital ships.
  • The scrapping of existing or planned capital ships to give a 5:5:3:1.75:1.75 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 UK delegation, but they were controversial with the British public. It would no longer be possible for Britain to have adequate fleets in the North Sea, the Mediterranean, and the Far East simultaneously. That provoked outrage from parts of the Royal Navy.

Nevertheless, there was huge demand for the UK to agree. The risk of war with the United States was increasingly regarded as merely theoretical, as there were very few policy differences between the two Anglophone powers. Naval spending was also unpopular in both the UK and its dominions. Furthermore, Britain was implementing major decreases of its budget because of the post–World War I recession.[9]

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 United States 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 a big enough margin of victory to be able to win the subsequent engagement and so a 5:3 ratio, or 60%, was unacceptable. Nevertheless, the director of the delegation, Katō Tomosaburō, preferred accepting 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 capital ships and 18% of the GDP that the Americans did.

Japanese aircraft carrier Akagi 1925
Akagi (a former Japanese battlecruiser converted to an aircraft carrier) being relaunched during April 1925.

His opinion was opposed strongly by 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, which was that in the event of war, the United States would be able to build indefinitely more warships, because of its huge industrial power, and so Japan needed to prepare as thoroughly as possible for the inevitable conflict with America.

Katō Tomosaburō was finally able to persuade the Japanese high command to accept the Hughes proposals, but the treaty was for years a cause of controversy in the navy.[10]

The French delegation initially responded negatively to the idea of reducing its capital ships tonnage to 175,000 tons and demanded 350,000, slightly above Japan. In the end, concessions regarding cruisers and submarines helped persuade the French to agree to the limit on capital ships.[11] Another issue that was considered critical by the French representatives was Italy's request of substantial parity, which was considered unsubstantiated; however, pressure from the US and UK delegations caused them to accept it. That was considered a great success by the Italian government, but parity would never actually be attained.[12]

There was much discussion about the inclusion or exclusion of individual warships. In particular, the Japanese delegation was keen to retain their newest battleship Mutsu, which had been funded with great public enthusiasm, including donations from schoolchildren.[13] That resulted in provisions to allow the United States and Britain to construct equivalent ships.

Cruisers and destroyers

HMS Hawkins quayside
Hawkins lead ship for the Hawkins class cruisers alongside the quay, probably during Interwar period.

Hughes proposed to limit secondary ships (cruisers and destroyers) 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 imperial commitments but the United States and Japan only 300,000 and 250,000 respectively, proved equally contentious. Thus, the idea of limiting total cruiser tonnage or numbers was rejected entirely.[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, then being constructed. That coincided with the USA's requirements for cruisers for Pacific Ocean operations and also with Japanese plans for the Furutaka class. The suggestion was adopted with little debate.[11]


A major British demand during the negotiations was the complete abolition of the submarine, which had proved so effective against them in the war. However, that proved impossible, particularly as a result of French opposition; they demanded an allowance of 90,000 tons of submarines[14] and so the conference ended without an agreement for restricting submarines.[15]

Pacific bases

Article XIX of the Treaty also prohibited Britain, Japan, and the United States 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.[16]


Tonnage limitations
Country Capital ships Aircraft carriers
British Empire 525,000 tons
(533,000 tonnes)
135,000 tons
(137,000 tonnes)
United States 525,000 tons
(533,000 tonnes)
135,000 tons
(137,000 tonnes)
Empire of Japan 315,000 tons
(320,000 tonnes)
81,000 tons
(82,000 tonnes)
France 175,000 tons
(178,000 tonnes)
60,000 tons
(61,000 tonnes)
Italy 175,000 tons
(178,000 tonnes)
60,000 tons
(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.

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 (Argus, Furious, Langley and Hosho) were declared "experimental" and not counted (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 and for the UK to complete two new ships in accordance with the treaty limits.

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.


Battleship building scatter graph 1905 onwards
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 then 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 power and 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 in the absence of Japan or Italy, it was largely ineffective.

There were fewer effects on cruiser building. While the treaty specified 10,000 tons and 8-inch guns as the maximum size of a cruiser, 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 cruisers", which gave further cause for concern.[17] Subsequent naval treaties sought to address this, by limiting cruiser, destroyer and submarine tonnage.

Unofficial effects of the treaty included the end of the Anglo-Japanese Alliance. It was not part of the Washington Treaty in any way, but the American delegates had made it clear they would not agree to the treaty unless the UK ended its alliance with the Japanese. [18]

Japanese denunciation

Japanese denonciation of the Washington Treaty 29 December 1934
Japanese denunciation of the Washington Naval Treaty, 29 December 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.

Many Japanese considered the 5:5:3 ratio of ships as another snub by the West, though it can be argued that the Japanese had a greater force concentration than the U.S Navy or the Royal Navy. It 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 contributed to the deterioration of the relationship between the United States and Japanese governments. Some have also argued that the treaty was one major factor in prompting Japanese expansionism by the Fleet Faction during the early 1930s.[19] The perception of unfairness resulted in Japan's renunciation of the Second London Naval Treaty during 1936.

Yamato during Trial Service
Yamato during sea trials, October 1941. It displaced 72,800 tonnes at full load.

Isoroku Yamamoto, who later masterminded the attack of Pearl Harbor, argued that Japan should remain in the treaty. His 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 US production advantage of which he was an expert 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."[20] 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.

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.

As it 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.


  1. ^ League of Nations Treaty Series, vol. 25, pp. 202–227.
  2. ^ a b Marriott 2005, p. 9.
  3. ^ Potter 1981, p. 232.
  4. ^ Evans & Peattie 1997, p. 174.
  5. ^ Potter 1981, p. 233.
  6. ^ Kennedy 1983, p. 274.
  7. ^ Marriott 2005, p. 10.
  8. ^ Jones 2001, p. 119.
  9. ^ Kennedy 1983, pp. 275–276.
  10. ^ Evans & Peattie 1997, pp. 193–196.
  11. ^ a b c Marriott 2005, p. 11.
  12. ^ Giorgerini, Giorgio (2002). Uomini sul fondo : storia del sommergibilismo italiano dalle origini a oggi. Milano: Mondadori. pp. 84–85. ISBN 978-8804505372.
  13. ^ Evans & Peattie 1997, p. 197.
  14. ^ Marriott 2005, pp. 10–11.
  15. ^ Birn, Donald S. (1970). "Open Diplomacy at the Washington Conference of 1921–2: The British and French Experience". Comparative Studies in Society and History. 12 (3): 297. doi:10.1017/S0010417500005879.
  16. ^ Evans & Peattie 1997, p. 199.
  17. ^ Marriott 2005, p. 3.
  18. ^ Howarth 1983, p. 167.
  19. ^ Conway's All the World's Fighting Ships 1922–1946. Conway Maritime Press. 1980. p. 3. ISBN 978-0851771465.
  20. ^ Howarth 1983, p. 152.


  • Evans, David; Peattie, Mark (1997), Kaigun: Strategy, Tactics and Technology in the Imperial Japanese Navy, 1887–1941, Annapolis: Naval Institute Press, ISBN 978-0-87021-192-8.
  • Kaufman, Robert Gordon (1990), Arms Control During the Pre-Nuclear Era: The United States and Naval Limitation Between the Two World Wars, New York: Columbia University Press, ISBN 978-0-231-07136-9
  • Kennedy, Paul (1983), The Rise and Fall of British Naval Mastery, London: Macmillan, ISBN 978-0-333-35094-2
  • Marriott, Leo (2005), Treaty Cruisers: The First International Warship Building Competition, Barnsley: Pen & Sword, ISBN 978-1-84415-188-2
  • Potter, E, ed. (1981), Sea Power: A Naval History (2nd ed.), Annapolis: Naval Institute Press, ISBN 978-0-87021-607-7
  • Jordan, John (2011), Warships after Washington: The Development of Five Major Fleets 1922–1930, Seaforth Publishing, ISBN 978-1-84832-117-5
  • Jones, Howard (2001), Crucible of power: a history of US foreign relations since 1897, Rowman & Littlefield, ISBN 978-0-8420-2918-6
  • Howarth, Stephen (1983), The Fighting Ships of the Rising Sun, Atheneum, ISBN 978-0-689-11402-1
  • Limitation of Naval Armament, treaty, 1922

External links

203mm/50 Modèle 1924 gun

The 203mm/50 Modèle 1924 was a medium naval gun of the French Navy.

The type was used on the Duquesne and Suffren classes of heavy cruisers as main battery, mounted in four twin turrets weighing 180 tonnes each. The calibre of 203 mm (8 inches) was characteristic of heavy cruisers built as a result of limitations imposed by the Washington Naval Treaty of 1922.

5"/25 caliber gun

The 5"/25 caliber gun (spoken "five-inch-twenty-five-caliber") entered service as the standard heavy anti-aircraft (AA) gun for United States Washington Naval Treaty cruisers commissioned in the 1920s and 1930s. The goal of the 5"/25 design was to produce a heavy AA gun that was light enough to be rapidly trained manually. The gun was also mounted on pre-World War II battleships and aircraft carriers until replaced by the standard dual-purpose 5"/38 caliber gun, which was derived from the 5"/25 and was similar except for the barrel length. Guns removed from battleships were probably converted for submarine use by late 1943, while a purpose-built variant for submarines was available in mid-1944, and was widely used by them. United States naval gun terminology indicates the gun fired a projectile 5 inches (127 mm) in diameter, and the barrel was 25 calibers long (that is, for a 5" bore and a barrel length of 25 calibers, 5" x 25 = 125", or about 3.2 meters).

Amagi-class battlecruiser

The Amagi class (天城型, Amagi-gata) was a series of four battlecruisers planned for the Imperial Japanese Navy (IJN) as part of the Eight-eight fleet. The ships were to be named Amagi, Akagi, Atago, and Takao (initially named Ashitaka), after the mountains Amagi, Akagi, Atago, and Takao. The Amagi design was essentially a lengthened version of the Tosa-class battleship, but with a thinner armored belt and deck and a modified secondary battery arrangement.Limitations imposed by the 1922 Washington Naval Treaty prevented the class from being completed as designed. However, the treaty had a limited allowance for hulls already under construction to be converted into aircraft carriers. Amagi and Akagi were both intended for conversion, but an earthquake damaged the hull of Amagi so extensively that the ship was scrapped. Akagi was reconstructed as an aircraft carrier and served with distinction as part of the Kido Butai during the Second World War, participating in the Japanese attack on Pearl Harbor before being sunk at the Battle of Midway.

BL 7.5-inch Mk VI naval gun

The BL 7.5-inch gun Mark VI was the 45 calibre naval gun forming the main battery of Royal Navy Hawkins-class cruisers. These ships with seven single gun mounts were significant to the cruiser limitations defined by the Washington Naval Treaty.

Eight-eight fleet

The Eight-Eight Fleet Program (八八艦隊, Hachihachi Kantai) was a Japanese naval strategy formulated for the development of the Imperial Japanese Navy in the first quarter of the 20th century, which stipulated that the navy should include eight first-class battleships and eight armoured cruisers or battlecruisers.

Fleet Faction

The Fleet Faction (艦隊派, Kantai-ha) was an unofficial and informal political faction within the Imperial Japanese Navy in the 1920s and 1930s of officers opposed to the conditions imposed by the Washington Naval Treaty.

Fleet carrier

A fleet carrier is an aircraft carrier designed to operate with the main fleet of a nation's navy. The term was developed during World War II, to distinguish it from the escort carrier and other lesser types. In addition to many medium-sized carriers, supercarriers, as well as some light carriers, are also classed as fleet carriers.

Heavy cruiser

The heavy cruiser was a type of cruiser, a naval warship designed for long range and high speed, armed generally with naval guns of roughly 203 mm (8 inches) in caliber, whose design parameters were dictated by the Washington Naval Treaty of 1922 and the London Naval Treaty of 1930.

The heavy cruiser is part of a lineage of ship design from 1915 through the early 1950s, although the term "heavy cruiser" only came into formal use in 1930. The heavy cruiser's immediate precursors were the light cruiser designs of the 1900s and 1910s, rather than the armoured cruisers of before 1905. When the armoured cruiser was supplanted by the battlecruiser, an intermediate ship type between this and the light cruiser was found to be needed—one larger and more powerful than the light cruisers of a potential enemy but not as large and expensive as the battlecruiser so as to be built in sufficient numbers to protect merchant ships and serve in a number of combat theaters.

With their intended targets being other cruisers and smaller vessels, the role of the heavy cruiser differed fundamentally from that of the armored cruiser. Also, the heavy cruiser was designed to take advantage of advances in naval technology and design. Typically powered by oil-fired steam turbines rather than the reciprocating steam engines of the armoured cruiser, heavy cruisers were capable of far faster speeds and could cruise at high speed much longer time than could an armoured cruiser. They used uniform main guns, mounted in center-line superfiring turrets rather than casemates. Casemate guns and a mixed battery were eliminated to make room for above deck torpedoes, and ever increasing and more effective anti-aircraft armaments. They also benefited from the superior fire control of the 1920s and continually upgraded through the 1950s. Late in the development cycle radar and electronic countermeasure would also appear and rapidly gain in importance. These developments meant that the heavy cruiser was an overall more powerful ship type than the armoured cruiser had been.

Japanese battleship Satsuma

Satsuma (薩摩) was a semi-dreadnought battleship built for the Imperial Japanese Navy (IJN) in the first decade of the 20th century. Lead ship of her class, she was the first battleship built in Japan. She was named for Satsuma Province, now a part of Kagoshima prefecture. The ship saw no combat during World War I, although she led a squadron that occupied several German colonies in the Pacific Ocean in 1914. Satsuma was disarmed and sunk as a target in 1922–24 in accordance with the terms of the Washington Naval Treaty of 1922.

Katori-class battleship

Not to be confused with the Katori-class cruisers.

The Katori class (香取型戦艦, Katori-gata senkan) was a two-ship class of pre-dreadnought battleships built for the Imperial Japanese Navy (IJN) in the early 1900s. As Japan lacked the industrial capacity to build such warships itself, they were designed and built in the UK. They were the last battleships to be built for Japan at overseas shipyards, and the last to be equipped with a ram. The ships were delivered after the end of the Russo-Japanese War of 1904–05. They saw no action during World War I, although both were present when Japan joined the Siberian Intervention in 1918. They were disarmed and scrapped in 1923–25 in accordance with the terms of the Washington Naval Treaty of 1922.

Kii-class battleship

The Kii-class battleship was a planned class of four fast battleships to be built for the Imperial Japanese Navy (IJN) during the 1920s. Only two of the ships received names. They were intended to reinforce Japan's "eight-eight fleet" of eight battleships and eight battlecruisers after the United States announced a major naval construction program in 1919. However, after the signing of the Washington Naval Treaty in 1922, work on the ships was suspended; one pair was cancelled in November 1923 and the other in April 1924.

Myōkō-class cruiser

The four Myōkō-class cruisers (妙高型巡洋艦, Myōkō-gata jun'yōkan) were built for the Imperial Japanese Navy in the late 1920s. Three were lost during World War II.

The ships of this class displaced 11,633 tons (standard), were 201 metres (659 ft) long, and were capable of 36 knots (67 km/h; 41 mph). They carried two aircraft and their main armament was ten 20.3-centimetre (8 in) guns in five twin turrets. At the time, this was the heaviest armament of any cruiser class in the world. They were also the first cruisers the Japanese Navy constructed that exceeded the (10,000 ton) limit set by the Washington Naval Treaty.

Pensacola-class cruiser

The Pensacola class was a class of United States Navy heavy cruiser, the first "treaty cruisers" designed under the limitations set by the Washington Naval Treaty, which limited cruisers to a maximum of 10,000 long tons (10,160 t) displacement and a maximum main battery caliber of 8-inch (203 mm).


Scuttling is the deliberate sinking of a ship by allowing water to flow into the hull.

This can be achieved in several ways—seacocks or hatches can be opened to the sea, or holes may be ripped into the hull with brute force or with explosives. Scuttling may be performed to dispose of an abandoned, old, or captured vessel; to prevent the vessel from becoming a navigation hazard; as an act of self-destruction to prevent the ship from being captured by an enemy force (or, in the case of a vessel engaged in illegal activities, by the authorities); as a blockship to restrict navigation through a channel or within a harbor; to provide an artificial reef for divers and marine life; or to alter the flow of rivers.

Standard-type battleship

The Standard-type battleship was a series of twelve battleships across five classes ordered for the United States Navy between 1911 and 1916 and commissioned between 1916 and 1923. These were considered super-dreadnoughts, with the ships of the final two classes incorporating many lessons from the Battle of Jutland.

Each vessel was produced with a series of progressive innovations, which contributed to the pre-World War II arms race. The twelve vessels constituted the US Navy's main battle line in the interwar period, while many of the ten earlier dreadnoughts were scrapped or relegated to secondary duties. Restrictions under the 1922 Washington Naval Treaty limited total numbers and size of battleships and had required some under construction to be cancelled, so it was not until the onset of World War II that new battleships were constructed. On December 7, 1941, eight were at Pearl Harbor, one at Bremerton, Washington, and three were assigned to the Atlantic Fleet.

Treaty Faction

The Treaty Faction (条約派, Jōyaku-ha) was an unofficial and informal political faction within the Imperial Japanese Navy in the 1920s-1930s of officers supporting the Washington Naval Treaty.

Treaty battleship

A treaty battleship was a battleship built in the 1920s or 1930s under the terms of one of a number of international treaties governing warship construction. Many of these ships played an active role in the Second World War, but few survived long after it.

In the Washington Naval Treaty of 1922, the world's five naval powers agreed to abide by strict restrictions on the construction of battleships and battlecruisers, in order to prevent an arms race in naval construction such as preceded the Great War. The Treaty limited the number of capital ships possessed by each signatory, and also the total tonnage of each navy's battleships. New ships could only be constructed to replace the surviving ships as they retired after 20 years' service. Furthermore, any new ship would be limited to guns of 16-inch caliber and a displacement of 35,000 tons.

The Washington Treaty limits were extended and modified by the London Naval Treaty of 1930 and the Second London Naval Treaty of 1936. During the 1930s, however, the effectiveness of these agreements broke down, as some signatory powers (in particular Japan) withdrew from the treaty arrangements and others only paid lip service to them. By 1938, Britain and the USA had both invoked an 'escalator clause' in the Second London Treaty which allowed battleships of up to 45,000 tons displacement, and the Treaty was effectively defunct.

The strict limits on displacement forced the designers of battleships to make compromises which they might have wished to avoid given the choice. The 1920s and 1930s saw a number of innovations in battleship design, particularly in engines, underwater protection, and aircraft.

USS Washington (BB-47)

USS Washington (BB-47), a Colorado-class battleship, was the second ship of the United States Navy named in honor of the 42nd state. Her keel was laid down on 30 June 1919, at Camden, New Jersey, by the New York Shipbuilding Corporation. She was launched on 1 September 1921, sponsored by Miss Jean Summers, the daughter of Congressman John W. Summers of Washington.

On 8 February 1922, two days after the signing of the Washington Naval Treaty for the Limitation of Naval Armaments, all construction work ceased on the 75.9%-completed superdreadnought. She was sunk as a gunnery target on 26 November 1924, by the battleships New York and Texas.

Washington Naval Conference

The Washington Naval Conference, also named the Washington Arms Conference or the Washington Disarmament Conference, was a military conference called by U.S. President Warren G. Harding and held in Washington, D.C., from 12 November 1921 to 6 February 1922. Conducted outside the auspice of the League of Nations, it was attended by nine nations—the United States, Japan, China, France, Britain, Italy, Belgium, Netherlands, and Portugal—regarding interests in the Pacific Ocean and East Asia. Soviet Russia was not invited to the conference. It was the first arms control conference in history, and as Kaufman, 1990 shows, it is studied by political scientists as a model for a successful disarmament movement.

Held at Memorial Continental Hall in downtown Washington DC, it resulted in three major treaties: Four-Power Treaty, Five-Power Treaty (more commonly known as the Washington Naval Treaty), the Nine-Power Treaty, and a number of smaller agreements. These treaties preserved peace during the 1920s but were not renewed in the increasingly hostile world of the Great Depression.

Interwar Naval Arms Limitation
Treaties of Japan
Bakumatsu period
Meiji period
World War III
During Cold War

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