Japan renounces the naval treaties

On 29 December 1934 the Japanese ambassador in Washington, Hiroshi Saitō, handed the Secretary of State, Cordell Hull, a note in which the government in Tokyo gave notice of its intention to terminate the Washington Naval Treaty of 1922. Under Article XXIII, the treaty would in that case cease to bind all its signatories on 31 December 1936. Japan justified the step on the grounds that the fleet ratios fixed in Washington did not guarantee its security, and proposed a new agreement based on the principle of equality. It was the end of the system of naval arms limitation that had kept the balance in the Pacific for twelve years. From 1937 the world’s three largest navies could once again build without any quantitative limits.

It is often said that on this day Japan renounced both the Washington Treaty and the London Naval Treaty. Strictly speaking, the note of 29 December concerned only the Washington Treaty. The London Treaty of 1930 needed no notice of termination, because its most important provisions, with their limits on cruisers, destroyers and submarines, expired on 31 December 1936 in any case under its Article 23. The treaty merely provided that the powers would meet in 1935 to prepare a new agreement. Japan announced that it would not accept an extension on the existing terms, and in January 1936 it walked out of that conference. In practice, therefore, the December note did away with both treaties, although formally it terminated only one.

A deadline that expired at the end of the year

The date of the note was no accident. Article XXIII of the Washington Treaty stipulated that the treaty would remain in force until 31 December 1936 and that, if none of the powers gave notice of its intention to terminate it two years before that date, it would continue in force until two years after the day on which one of them did so. Notice by a single state ended the treaty for all. Notice was to be given to the government of the United States, which passed it on to the other signatories. Japan, wanting to free itself from the treaty at the earliest possible date, therefore had to deliver its note before the end of 1934. It did so two days before the deadline.

The road to renunciation

From the outset the Washington Treaty had bitter opponents in the Imperial Japanese Navy. To them the 5:5:3 ratio in capital ships between the United States, Britain and Japan was a humiliation and proof that the West did not treat Japan as an equal. The dispute over the London Treaty in 1930 split the navy into the Treaty Faction, whose leaders believed that Japan could not afford a race with America, and the Fleet Faction, grouped around Admiral Kanji Katō and Vice Admiral Nobumasa Suetsugu, which demanded that the limits be scrapped. After 1931 the Fleet Faction gained the upper hand. From 1932 the Chief of the Navy General Staff was Prince Hiroyasu Fushimi, a member of the imperial family, and in 1933–1934 the Navy Minister, Admiral Mineo Ōsumi, retired many admirals of the Treaty Faction.

Japan’s position in the world had also changed. After the Mukden incident and the proclamation of Manchukuo, Japan found itself isolated, and on 27 March 1933 it left the League of Nations. A few months later Germany left the League as well. In April 1934 the Japanese Foreign Ministry spokesman, Eiji Amau, declared that Japan opposed military and financial assistance to China by other powers – a statement the press dubbed Japan’s Monroe Doctrine for East Asia. Limits accepted in 1922 in return for Japanese commitments towards China fitted the Tokyo government’s policy less and less.

The United States, which under President Herbert Hoover had not even built as many ships as the treaties allowed, also changed course. In 1933 President Franklin Delano Roosevelt allocated public works funds to shipbuilding, and on 27 March 1934 he signed the Vinson–Trammell Act, which provided for building the fleet up to the full tonnage permitted by the treaties. Japanese admirals saw this as a sign that American superiority would soon grow. They believed that under the treaties Japan had no chance of offsetting it, whereas without them it could at least attempt qualitative superiority. In March 1934 the new torpedo boat Tomozuru, overloaded with armament so that, despite her small displacement, she could match larger ships, capsized in a storm. The accident showed how far designers were going to get round the limits.

In July 1934 Ōsumi threatened to resign if the government did not agree to abandon the treaties. On 8 July the retired admiral Keisuke Okada, who in 1930 had been one of the moderate supporters of the London Treaty, became Prime Minister. He was not strong enough to stand up to the navy. In September 1934 the government agreed in principle to terminate the Washington Treaty. The Foreign Minister, Kōki Hirota, supported the decision, but it was resolved to give notice only after preliminary talks in London.

The talks in London

The London Treaty provided that the powers would meet in 1935 to conclude a new agreement. In the autumn of 1934 preliminary talks between Britain, the United States and Japan were held in London. Japan was represented by its ambassador in London, Tsuneo Matsudaira, and Rear Admiral Isoroku Yamamoto, promoted to vice admiral in November. The Americans were led by the diplomat Norman Davis. Yamamoto, a former attaché in Washington who knew the strength of American industry, was to present the position fixed in Tokyo: Japan would no longer accept any ratio. It demanded a common upper limit on tonnage for all the powers – in practice, parity with America and Britain – and the abolition or drastic limitation of offensive weapons, above all battleships and aircraft carriers.

The Americans and the British rejected these demands. For the United States, which had to maintain a fleet in two oceans, and for Britain, which defended the sea lanes of an entire empire, parity with Japan would have meant Japanese superiority in the western Pacific. The British looked for a compromise. Part of the government, including the Chancellor of the Exchequer, Neville Chamberlain, even considered a rapprochement with Japan, because at the beginning of 1934 the Defence Requirements Committee had concluded that Britain could not face Japan in the Far East and Germany in Europe at the same time. No compromise was found, however. The talks were broken off in December 1934 without agreement. Yamamoto was embittered, all the more so because at the same time Ōsumi had retired his friend Admiral Teikichi Hori, one of the last leaders of the Treaty Faction. In his letters he complained that he had been used merely as a tool.

The note and Hull’s reply

Once the decision had been approved by the Emperor’s Privy Council, Ambassador Saitō delivered the note to the State Department. That same day Hull issued a statement. He said that every state had the right not to renew the treaty, but that the American government regretted the decision, because the treaties had protected the interests of all the signatories. He pointed out that in London the dispute had been over whether disarmament should rest on equality of armaments or on equal security for each state, and that the United States favoured the latter principle. He recalled that the treaty remained in force until the end of 1936, leaving two years for talks. In accordance with the treaty, the State Department passed the note on to Britain, France and Italy.

The end of the treaty era

The two years Hull spoke of brought no agreement. On 9 December 1935 the Second London Naval Conference opened. Japan renewed its demand for a common upper limit, and when this was rejected, its delegation walked out on 15 January 1936. In March 1936 the United States, Britain and France concluded a new treaty that limited only the size and armament of individual ships, not the size of fleets. On 31 December 1936 both treaties, the Washington and the London, expired. With them went the ban on expanding bases and fortifications on the islands of the western Pacific, which since 1922 had bound America in the Philippines and Guam, Britain in Hong Kong, and Japan in the Kurils, the Bonin Islands, the Ryukyus and Taiwan.

Japan made use of its freedom at once. As early as 1937 the keel of the battleship Yamato was laid down at the Kure naval yard, followed soon afterwards by that of her sister ship Musashi. They displaced more than 60,000 tons, carried 460 mm guns and were built in the utmost secrecy. The Japanese admirals calculated that the Americans, whose ships had to pass through the Panama Canal, would not build vessels as large. The United States, however, answered the race with numbers. Successive acts, of 1938 and above all the “Two-Ocean Navy” Act of July 1940, launched a building programme that Japan could not match. The reckoning that Admiral Tomosaburō Katō had warned of in 1922 proved correct: without the treaties Japan gained no superiority, but lost the limits that had also constrained its far stronger rival.

Renouncing the treaties was also another step in Japan’s move away from cooperation with the Western powers towards a policy of force, pursued first alone and then in alliance with Germany. In 1936 Tokyo signed the Anti-Comintern Pact with Germany, in 1937 it began a full-scale war with China, and in 1940 it concluded the Tripartite Pact with Germany and Italy. Yamamoto, who had defended the Japanese position in London in vain, became commander of the Combined Fleet in 1939 and prepared the attack on Pearl Harbor. The unfinished attempt to preserve the naval order in 1934–1936 was the last moment at which Japan and the United States discussed their fleets at the conference table rather than preparing them for war.