The Washington Naval Treaty

On 6 February 1922, in Memorial Continental Hall in Washington, the Washington Conference came to an end – the first meeting of the great powers in history at which a limitation of armaments was actually agreed. That day representatives of the United States, the British Empire, Japan, France and Italy signed the Treaty for the Limitation of Naval Armament, known as the Five-Power Treaty or simply the Washington Naval Treaty. It set the tonnage of battleships and aircraft carriers each signatory was allowed, halted the construction of new capital ships for ten years and banned the expansion of fortifications on the islands of the western Pacific. The same day a Nine-Power Treaty on China was also signed. Together with the Four-Power Treaty concluded earlier, the Washington agreements created an order that kept the peace in the Pacific for a decade. When Japan tore it up in the 1930s, the road to war in the Pacific lay open.

A race nobody wanted

The First World War destroyed the German navy. Its best ships scuttled themselves at Scapa Flow, and the Treaty of Versailles allowed Germany to keep only a handful of obsolete battleships. Russia had sunk into revolution and civil war, and Austria-Hungary had ceased to exist. Three great navies remained on the seas – the British, the American and the Japanese – together with two smaller ones, the French and the Italian. The common enemy had vanished, and with it the reason to share spheres of influence.

As early as 1916 the United States had adopted a programme to build a navy “second to none”. After the war new battleships and battlecruisers were taking shape in American shipyards. Japan responded with its “eight-eight” fleet programme – eight modern battleships and eight battlecruisers – which the parliament in Tokyo approved in 1920. Naval spending was then swallowing about a third of the state budget. Britain, in debt and in recession, planned ships of its own, although it could barely pay for them. An arms race loomed like the Anglo-German one before 1914, only this time in the Pacific and between former allies.

Tension between Washington and Tokyo had been growing for years. Japan had come out of the war with gains: the German islands north of the equator, which it received as a League of Nations mandate, and the German rights in the Chinese province of Shandong, which had been awarded to it in Paris over China’s objections. Its troops were still stationed in the Russian Far East, which they had entered during the Siberian intervention. Tokyo, for its part, remembered the humiliation of 1919, when the victors rejected the Japanese racial equality proposal, and the American laws aimed at Japanese immigrants in California. The Americans also viewed with suspicion the Anglo-Japanese Alliance of 1902, which was just then due for renewal. In the event of an American–Japanese conflict it could, in theory, place Britain on Japan’s side.

Hughes’s invitation

In the United States arms limitation was a popular cause. The Senate had rejected the Treaty of Versailles and the League of Nations, but public opinion, the churches, and women’s and pacifist organisations wanted America to contribute to peace in some other way, and taxpayers did not want to pay for new battleships. In the summer of 1921 Congress adopted a resolution by the Republican senator William Borah calling on the president to negotiate fleet reductions with Britain and Japan. The new president, Warren Harding, who had succeeded Woodrow Wilson in March 1921, entrusted the matter to Secretary of State Charles Evans Hughes. In the summer of 1921 Hughes invited the four naval powers to Washington, and for the talks on the Far East also China, Belgium, the Netherlands and Portugal. Defeated Germany and Soviet Russia were not invited.

The conference opened on 12 November 1921, the day after the burial of the Unknown Soldier at Arlington Cemetery. Delegates, diplomats and hundreds of journalists filled the hall. The Americans were led by Hughes himself; the delegation included the former secretary of state Elihu Root, the Republican chairman of the Senate Foreign Relations Committee, Henry Cabot Lodge, and the leader of the Democratic minority in the Senate, Oscar Underwood. The presence of senators from both parties was meant to ease ratification and prevent a repeat of the Versailles fiasco. The British delegation was led by the former prime minister Arthur Balfour, the French by Prime Minister Aristide Briand, who soon returned to Paris and left matters to René Viviani, and the Italian by Senator Carlo Schanzer. At the head of the Japanese delegation stood the navy minister, Admiral Tomosaburō Katō, accompanied by the ambassador in Washington, Kijūrō Shidehara, and Prince Iesato Tokugawa, president of the House of Peers. In Tokyo, where Prime Minister Takashi Hara had been assassinated on 4 November and Crown Prince Hirohito became regent on 25 November, the government set itself the goal of an agreement, but without giving up Japan’s position in China.

“The way to disarm is to disarm”

Hughes opened with a stroke nobody expected. By custom the first session was meant to be ceremonial and devoid of substance. Instead, after a brief welcome, the secretary of state set out a concrete plan. He proposed a ten-year holiday in capital-ship construction, the cancellation of all battleships under construction or planned, and the scrapping of some older ones. He named the ships to be scrapped – not only American ones, but British and Japanese ones too. Altogether, according to the calculations of the time, the three powers were to get rid of 66 capital ships, existing and under construction, displacing nearly 1.9 million tons: 30 American, 23 British and 17 Japanese. The remaining fleets were to stand in a ratio close to the existing balance of power, roughly 5:5:3 for America, Britain and Japan.

The impression was enormous. The British military correspondent Charles à Court Repington wrote that in under an hour Hughes had sunk more ships than all the admirals of the world had sunk over the centuries. The admirals, especially the British and Japanese, were shaken, but public opinion around the world greeted the plan with enthusiasm, and rejecting it became politically costly for any government.

The Americans held one more trump card that the others knew nothing about. The so-called Black Chamber, a secret cipher bureau headed by Herbert Yardley, was reading the telegrams between Tokyo and the Japanese delegation. The American negotiators therefore knew the lowest limit of the concessions the Japanese government was prepared to make.

The dispute over “seven-tenths”

The talks with Japan were the hardest. Japanese naval doctrine held that Japan needed at least 70 per cent of the American fleet’s strength to defend itself against it. A ratio of 5:3, or 60 per cent, looked to the Japanese staff officers like a death sentence. The loudest protests came from the head of the delegation’s naval experts, Vice Admiral Kanji Katō, who considered war with America inevitable. The minister, Tomosaburō Katō, reasoned differently. He knew that Japan had neither the money nor the industry to win a race against the United States, and that without a treaty the balance of forces would be even worse for it. He persuaded the government in Tokyo to accept 60 per cent, but demanded two things in return.

The first was Japan’s newest battleship, Mutsu, built largely with public donations, including those of schoolchildren. Under Hughes’s plan she was to be scrapped, since she was not considered complete. Japan kept her, and in return the United States was allowed to complete two Colorado-class battleships and Britain to build two new ships, the future Nelson and Rodney. The second condition, far more important, was a ban on expanding bases in the Pacific. Article XIX of the treaty bound the United States, Britain and Japan to maintain the status quo in fortifications and naval bases on specified islands: the American Philippines, Guam and the Aleutians; British Hong Kong; and the Japanese Kurils, the Bonin Islands, Amami-Ōshima, the Ryukyus, Taiwan and the Pescadores. The ban did not cover Hawaii, Singapore, Australia or the Japanese home islands. In practice it meant that the Americans could not build a major base in the Philippines or on Guam, nor the British in Hong Kong. The western Pacific became the domain of the Japanese navy.

France demanded 350,000 tons of capital ships for itself, more than Japan, and fiercely objected to being placed on a par with Italy. Under American and British pressure it gave way, but in return refused any limits on cruisers, destroyers and submarines. The British wanted a total ban on submarines, which had nearly starved their island during the war. France blocked it.

What the treaty laid down

The Five-Power Treaty had 24 articles. The most important were the limits on the total tonnage of capital ships – battleships and battlecruisers: 525,000 tons each for the United States and the British Empire, 315,000 for Japan and 175,000 each for France and Italy. The ratio is usually written as 5:5:3:1.75:1.75, although strictly the figures give 1.67 for France and Italy. A single capital ship could have a standard displacement – newly defined for the purposes of the treaty – of no more than 35,000 tons and guns of up to 16 inches (406 mm). For aircraft carriers, a new weapon whose importance no one yet properly understood, America and Britain were allotted 135,000 tons, Japan 81,000 and France and Italy 60,000 each. A single carrier could displace 27,000 tons, but each state could convert two unfinished capital-ship hulls into carriers of up to 33,000 tons. This is how the American Lexington and Saratoga and the Japanese Akagi and Kaga came into being – Kaga converted from a battleship after the hull of the battlecruiser Amagi, earmarked for conversion, was damaged in the earthquake of 1923.

Other warships were not limited in number or total tonnage. The treaty stipulated only that none of them could exceed 10,000 tons or carry guns larger than 8 inches (203 mm). It was also agreed that for ten years no new capital ships could be built, apart from the permitted exceptions, and that old ones could be replaced only after twenty years’ service. The treaty was to remain in force until 31 December 1936, and thereafter until two years after any signatory gave notice of termination.

Four powers and nine

The naval treaty was part of a wider settlement. On 13 December 1921 the United States, Britain, France and Japan had signed the Four-Power Treaty. The parties undertook to respect one another’s possessions in the islands of the Pacific and to consult one another in the event of a dispute. Its most important provision was the last article: when the treaty came into force, the Anglo-Japanese Alliance would lapse. The British, Canada especially, did not want to risk a quarrel with America, and the Americans made the whole agreement conditional on ending the alliance. For Japan it was a blow. For twenty years the alliance with the world’s greatest naval power had been the cornerstone of its policy. It was replaced by a non-binding formula of consultation.

On 6 February 1922, together with the naval treaty, all nine states at the conference signed the treaty on China. It bound the signatories to respect the sovereignty, independence and territorial and administrative integrity of China, and to observe the principle of equal opportunity for the trade of all nations – the American Open Door policy. It was the first multilateral treaty to give this principle legal force. It provided, however, for no sanctions. On the sidelines of the conference, through the good offices of Hughes and Balfour, China and Japan concluded a separate agreement on 4 February 1922 under which Japan returned to China the former German leased territory of Jiaozhou with the port of Qingdao (Tsingtao), while keeping economic influence in the Shandong railway. This dispute had poisoned Sino-Japanese relations since 1919 and had sparked the May Fourth Movement in China. Japan also announced the withdrawal of its troops from Siberia, which took place in the autumn of 1922.

Also signed on 6 February was a treaty on the use of submarines and poison gas in wartime, drafted by Root. It never came into force, because France did not ratify it.

Ratification and consequences

The US Senate approved the treaties in the spring of 1922. The Four-Power Treaty, in which some senators saw a hidden alliance, caused the most controversy. The other states ratified them over the following year, France last of all. The instruments of ratification of the naval treaty were exchanged in Washington on 17 August 1923, and it then came into force. On the same day the Anglo-Japanese Alliance formally ceased to exist.

The treaty brought about the largest voluntary reduction of navies in history. Dozens of battleships went to the breakers and construction of many new ones was halted. Governments saved enormous sums, and the era of capital-ship building ended for nearly fifteen years. For the first time in centuries Britain agreed to parity with another navy. Japan was recognised as the world’s third naval power, but with its inferiority formally written down. Hughes, and the whole world after him, saw Washington as proof that disarmament was possible. To this day the conference is regarded as the first successful arms control agreement.

The consequences had another side, too. Limiting capital ships diverted the rivalry to other classes. The limit of 10,000 tons and 8-inch guns for cruisers quickly became the standard every navy wanted to reach, and in the 1920s a race began to build so-called treaty cruisers. An attempt to halt it at the Geneva conference in 1927 failed, and the next was made in London in 1930. The conversion of hulls into carriers gave America and Japan large, fast ships that twenty years later became the backbone of their fleets.

The long shadow of Washington

In Japan the treaty had bitter enemies from the start. Some naval officers saw the 5:5:3 ratio as a humiliation, further proof that the West did not treat Japan as an equal. Two camps emerged in the navy. The Treaty Faction, the heirs of Tomosaburō Katō, held that Japan could not afford a race with America and that the limits also constrained the stronger side. The Fleet Faction, led by Kanji Katō and backed by the legendary Admiral Heihachirō Tōgō, demanded that the limits be thrown off. When in 1930 the government in Tokyo accepted further limits in London, the dispute turned into a political crisis that weakened civilian control over the armed forces.

The Washington agreements rested on the assumption that all the signatories wanted to preserve the existing state of affairs. When in September 1931 the Kwantung Army staged the Mukden incident and occupied Manchuria, Japan broke the Nine-Power Treaty. The Americans and the British could only protest, since the treaty provided for no sanctions. On 29 December 1934 Tokyo gave notice of termination of the naval treaty, which expired at the end of 1936. At the Second London Naval Conference in January 1936 the Japanese delegation, denied parity with America and Britain, walked out. In 1937, when the Second Sino-Japanese War broke out, the signatories of the Nine-Power Treaty met in Brussels – without Japan, which refused to attend – but did nothing. That same year the keel of the battleship Yamato, the largest capital ship in history, was laid down at the Kure shipyard, built in secret from the rest of the world.

Paradoxically, a treaty meant to prevent war in the Pacific shaped the course of that war. Because of the ban on expanding bases, in December 1941 the Philippines and Guam were weakly defended and fell quickly. The carriers built from the hulls of battleships condemned at Washington played a key role in the war: Akagi and Kaga led the attack on Pearl Harbor and were sunk at Midway. Admiral Isoroku Yamamoto, who in the 1920s had served as an attaché in Washington and defended the treaties because he knew Japan could not beat American industry, became commander of the Combined Fleet in 1939 and planned the strike on Pearl Harbor. The Washington order did not survive the 1930s, but for ten years it held back an arms race that without it would probably have begun much earlier.