Ambassador Castle’s Role in the Negotiations of the London Naval Conference

A turning point in Japanese-American relations may well have come in 1930, when William R. Castle, Jr., served for four months as ambassador to Tokyo during the time of the London Naval Conference. Castle’s task, generally overlooked by historians, was to obtain Japan’s cooperation at the meetings; his hope, which came to naught, was to link the Japanese closely to America’s desire for world peace.

Castle’s career had been varied. A former assistant dean of Harvard College, during the 1920s he had served in the State Department as chief of the division of Western European Affairs (1921-27) and as Assistant Secretary of State for Western Europe (1927-30). In 1930 President Herbert Hoover sent him to interpret the U. S. position to the government of Premier Yuko Hamaguchi, and to facilitate acceptance of what proved a complicated naval treaty. Castle hoped that a stable, democratic Japan could have a legitimate interest in China while serving as a bulwark against Russian expansion. He was prepared to recognize Japan’s aspirations for trade in China, while working to obtain concessions in naval armaments.

Before the talks began in London, President Hoover had taken measures to protect the American diplomatic position—appointing as ambassadors in the major capitals individuals who had sufficient distinction to lend prestige to his policy. He believed that the Japanese post would be Particularly sensitive and consulted his minister to Switzerland, Hugh Wilson, who responded that Castle was the best man for Japan. Before the invitation was made, Cas- He let the President know that he would accept, under the condition that the assignment cover only the period of the naval conference.

The Hoover administration was delighted to have a man who was in touch with American policy. Henry Cabot Lodge, Jr., then a journalist, wrote in The New York Herald Tribune of Castle’s special ability to sense the movements of public opinion.¹ The Japanese likewise looked forward to the mission. Because of the new envoy’s closeness to the President, they felt that America was taking into account their increasing international prestige.²

Although Castle’s instructions included no detail about negotiation with Tokyo, he did receive latitude to interpret American opinion and State Department positions. He was Responsible for communicating Japanese opinion, and his instructions stressed that he should communicate directly to the American delegation to the London conference, led by Secretary of State Henry L. Stimson.

The ambassador’s plan of action, which he did not substantially alter during his stay in Japan, was to concentrate on Japan’s foreign minister, Baron Kijuro Shidehara. Castle hoped to identify four or five other individuals who stood between the foreign minister and the Emperor and, hence, could prove helpful. The ambassador also hoped to Set to know “as many kinds of people as possible.”³ However, he quickly discovered that what seemed a common sense approach would hardly suffice against the extraordinary complexities of the naval conference. He found out that the Japanese Navy, and in reality the entire Japanese government, was not about to accept the ratio for British, American, and Japanese ships that Secretary Stimson was offering in London.⁴

The crucial problem at the London Conference was the so-called 10:10:6 ratio. Invented by a newspaperman present at the Washington Naval Conference of 1921-22—in the reduced form of 5:5:3—the ratio amounted, so Japanese critics had said at the time of the Washington Conference, to Rolls Royce: Rolls Royce: Ford. After the conference, the numbers 5:5:3 were scrawled across buildings in the cities of Japan, as another evidence of how Westerners had failed to appreciate a nation the late President Theodore Roosevelt once had described as the Anglo-Saxons of the Orient. Indeed, Japanese opinion was highly incensed by the ratio proposed by Washington.

The ratio agreed to in the early Twenties applied to only battleships and aircraft carriers. For battleships it was roughly comparable to hundreds of thousands of tons of displacement—500,000:500,000:300,000. The problem at London in 1930 was to extend the ratio to lesser categories of warships, that is, heavy and light cruisers, destroyers, and submarines. Opinion in Japan—and government policy—was strongly against extension, and desired not 10:10:6 but 10:10:7, and ideally equality.⁶

The special sticking point at London turned out to be what was known in interwar years as the heavy cruiser, a large ship that had become technically desirable because of the limitation of battleship tonnage at the Washington Conference. To prevent evasion of the battleship limitation, the diplomats had placed a limit on smaller vessels, stipulating that any ship over 10,000 tons displacement and with guns of more than eight inches would automatically be certifiable as a battleship. This sensible arrangement then became a sort of ideal definition for a heavy cruiser—the next largest ship to a battleship. In 1922 no cruiser had been built with a displacement of 10,000 tons and guns of eight inches. Immediately, the U. S. Navy undertook to build such ships, which became known as “treaty cruisers.” It is fairly clear that they chose the size because it was the largest possible. The British and Japanese navies followed suit, and by the mid-1920s, a veritable race in heavy cruisers was developing. The London Naval Conference met in an attempt to halt that race.

The Japanese believed that construction of such large cruisers by the United States threatened Japan’s control of the Western Pacific. Such, indeed, was the purpose of the U. S. Navy, although in retrospect it is clear that a dozen or so heavy cruisers would hardly have controlled that enormous reach of ocean that stretched from Hawaii westward to the Japanese Islands. In any event, the thought became reality, both in Washington and Tokyo. This, then, became the problem of Ambassador Castle.

Secretary of State Stimson seems never to have understood the nature of this treaty-cruiser problem. In addition, Castle soon discovered that his superior, negotiating in London, thought a 10:10:6 ratio in treaty cruisers— heavy cruisers—was easily possible. Castle’s presumed task in Tokyo was to relate the obvious (Stimson’s interpretation) to the Japanese, and perhaps as easily as Stimson had decided the issue, gain Japanese acceptance.

Stimson, far less than Castle, had little patience for the theoretical nature of the treaty cruiser’s architecture. A complicating factor was that the 10,000 tons displacement was not enough of a platform for eight-inch guns. Moreover, an eight-inch gun had to be machine-loaded, meaning only three shells in the air a minute, as opposed to a six-inch gun that could be hand loaded. This would result in 10-15 shells in the air per minute. Further, the weight of the shells was 250 compared with 100 pounds. Hence, if a light cruiser, the standard cruiser of the 1920s, could close the supposedly awful gap where it did not have the range, it could destroy a heavy cruiser by sheer numbers of shells in the air.⁵

Even before going to Japan, Castle had seen how awkward the treaty-cruiser issue was becoming and how dangerous it was for American-Japanese relations. In a letter to Hugh Wilson dated 29 January 1930 he wrote:

One thing we certainly missed at home was the very widespread demand for the 10:7 ratio. There is no use in saying that we should not consider ratios because the Japanese instantly point out that our entire policy is based on equal ratio with Great Britain. The Japanese government is certainly not going to capitulate right away on the matter, particularly at a time when capitulation would mean almost certainly defeat in the election of February 20.⁷

The Hamaguchi government’s insistence on a 10:7 ratio with the United States in the heavy cruisers had originated in a 10 October 1929 meeting at the residence of the naval minister. The entire cabinet, leaders of the opposition party, and members of the Privy Council expressed unity in seeking the 10:7 ratio. To all important political and naval groups, this ratio was crucial to the security of the empire. The Japanese demand, going into the conference, was founded specifically upon the avowed defensive strategy of Japan’s navy.

The U. S. Navy had assumed that the 10:6 ratio established for battleships and aircraft carriers at the Washington Conference could extend to all categories of ships. Throughout the London Conference the Japanese insisted that the 10:6 ratio applied only to capital warships, and any comprehensive armament control over other categories of warships would have to be settled at the 10:7 ratio. Hence, as the American delegation took ship to London in January of 1930, no preliminary agreement had been achieved. Secretary Stimson’s confidence that Japan would not insist on the 10:7 ratio because it needed relief from the expense of replacing old battleships accounted for his failure to arrive at a pre-conference arrangement.

As Castle’s suspicions of Japanese intransigence on the 10:7 ratio were confirmed by early reports from London, he began to discover division in the Japanese position. His analysis of inner circles of the Tokyo government revealed that Hamaguchi still hoped to produce a successful conference while enhancing Japan’s prestige. Before dissolution of the Diet in early 1930, the opposition party, the Seiyukai, made a loud but unsuccessful attempt to force the government to state that the 10:7 ratio was essential. “Big navy” supporters in Japan, prominent among the naval command, continued to insist that lessons of the battles of Tsushima in 1905 and Jutland in 1916 required the higher ratio.⁸

Castle also discovered that the chief Japanese concern was conflict with the Americans over China. By attempting to diminish Japan’s fear that America would challenge its interests in China, the United States could make agreement at London more likely and also establish a basis for long-range cooperation. Although Japan was “a powerful and faithful ally in the Far East,” he wrote to Hoover on 27 January 1930, “at present, it is a suspicious friend.”⁹

Castle shared Hoover’s long-standing belief that Japan was a possible check to Russian expansion in the Far East. Japanese desire for trade with China, he felt, was a reasonable demand, given their vulnerable economy. Indeed, Japan’s legitimate economic interests in China could be acceptable to America. “From every point of view,” he told the Japan Society of Boston on 9 December 1930, “the two nations need each other, and I think these people are not far wrong who assert that our continued friendship more than any other single thing depends on the peace of the world.”¹⁰

Castle also believed that neither pacifistic ideals nor agreements could guarantee peace. Rather, enlightened self-interest among major powers and the peaceful flow of world trade were the keys. In 1930, and from the perspective of both the United States and Japan, a unified, prosperous, independent China was in the best interest of each.

In a private letter written on 27 January 1930 to his old friend, Senator David Reed, the top U. S. representative at the London Conference, Castle expressed his dismay over the ingrained American fear of Japan:

It is a fantastic fear since I cannot imagine Congress declaring war on Japan because of anything Japan might do in China ... It is perfectly silly for us to pretend that Japan has not had special interests in Manchuria, and although the Japanese possession of the South Manchuria Railway may be irritating to the Chinese government, it is certainly not irritating to the Chinese people. Otherwise, they would not emigrate to Manchuria at the rate of 700,000 a year in order to live in safety and peace under the Japanese."

In his initial conversation with Shidehara, Castle stressed the above points as well as belief that the 10:7 ratio for Japan was unnecessary as America would not Possibly build beyond a 10:6 ratio. He stressed that armaments were an incitement to war. As was typical of State Department officials in the 1920s, Castle believed that military buildups had been one of the causes of World War I. Indeed, international tension did not so much cause armament races as races caused tension. Weapons tempted a country to try them.¹² Further, in a period when economic depression was worsening, he stressed the expense of military weapons. To the argument that arms gave jobs, his philosophy was that the money would have had benefit if it were used for constructive social purposes.¹³

As negotiation intensified in London, Castle focused on these themes both in public statements and in conversation. Despite a warning from the Acting Secretary of State, Joseph P. Cotton, that he should be careful in his “phraseology” in explaining American-Japanese relations, Castle pressed the two countries’ compatibility of interests.¹⁴ His first speech was to an audience of press reprcsentatives, and he called the countries’ aims identical and said that long-term self-interest would be predicated on a peaceful, sovereign China. The reception was positive. The influential Nichi-Nichi agreed that China was the crux of suspicion and hoped that Castle’s understanding of China’s importance to Japan was representative of future U. S. positions. Everywhere the ambassador went, he Pointed to Japanese-American cooperation in education, economy, medicine, and in rebuilding Tokyo after the destructive earthquake of 1923. Speaking to audiences at universities, hospitals, businessmen’s associations, and Specially the press, he emphasized goodwill and the advantages of cooperation.

The American press took immediate interest in this active ambassador. In his call for reduced armaments and respect, he seemed to echo the thoughts of many Americans who felt he had identified the residual source of international tension.¹⁵ Members of Congress quoted from Castle’s speeches to bolster their argument that the Japanese “bugaboo” was being used to keep the arms race going. Senator Hiram Johnson of California, however, Pondered publicly whether the ambassador had gone too far by implying that Japan would be the chief guarantor of Peace in the Pacific, much as the United States was in the Western Hemisphere.¹⁶

The period of preparatory discussion in London ended by 4 February 1930, when the American delegation rejected Japan’s claim for the 10:7 ratio. The head of the Japanese delegation, Wakatsuki Reijiro, protested that such a ratio was essential to Japanese security. Despite the offer of the U. S. delegation to accept 18 heavy cruisers, Wakatsuki repeated that a 10:6 ratio was a harbinger of U. S. aggression in the Pacific.

As Castle and much of the London Conference delegation anticipated, the Japanese response remained rigidly negative until 20 February when the elections were held in Japan. Castle again pointed out that the 70% ratio was “a political doctrine” and the sine qua non of the Japanese program.¹⁷

Ambassador Castle’s continued description of Japanese intransigence and his sensitivity with policies of the Hamaguchi government irritated Stimson. Stimson feared that the popular ambassador might, in his effort to win Japanese approval, lead the Japanese to anticipate changes in American naval policy. On 28 February, Stimson ordered the acting Secretary, Cotton, not to repeat to Tokyo any details regarding the London negotiations unless he ordered it. Stimson, understandably, wanted one voice to represent U. S. policy. Castle, however, never could rid himself of the feeling that Stimson’s action was in part caused by his embarrassment in being wrong about Japanese willingness to reduce their demands. In his extensive but unpublished memoirs of State Department affairs from 1914 to 1937, Castle later wrote:

Agreement with Great Britain was certainly of prime importance, but the urge to secure that agreement somewhat obscured the importance of reaching understandings before the conference should meet with the other nations as well, especially Japan. Both Washington and London brushed aside as of little importance the Japanese request for a 10:10:7 ratio at least, and as a result, this question very nearly wrecked the conference. There was no conception—and there should have been—of the tremendous popular feeling on this subject in Japan.¹⁸

Castle then cabled the American delegation that the elections had resulted in a decisive victory for Hamaguchi. Defeat of the opposition meant that the government had an unassailable position and could prosecute its policies in a decisive manner. More importantly, he reported:

I was told confidentially by Admiral Kichisaburo Nomura [Commander, Japanese Third Fleet] that when the position of the Japanese government in the Diet is uncertain, it is apt to take a strong attitude in foreign questions, and when it is firmly entrenched in the Diet, it is apt to take a conciliatory attitude. ... It was not meant by him at all that the government would not capitulate on the ratio which had been repeatedly pointed out by me as much more than a government demand, but that the government would be in a position to make compromises which before the public could be defended.¹⁹

The Japanese delegation again presented its proposal for a 10:7 ratio, and then proposed a compromise. Japan would accept 18 cruisers for the United States, if the American government would defer construction of the last three cruisers until 1935. Such a compromise might satisfy the American desire for the 10:6 ratio, while assuring Japan’s wish for a 10:7 ratio until 1936. In 1936, Japan would reopen discussion with the United States.

The proposal at first received a cool reception, but Stimson’s attitude changed when President Hoover noted on 5 March that even if given a slowdown in American construction, the Japanese Navy would be greatly inferior. Additional pressure to consider the Japanese offer came from Senators William E. Borah and Claude Swanson, who agreed with Castle that Japan need not be an inevitable opponent.²⁰

Stimson now notified Castle that he had authorized Senator Reed to accept the compromise, with one important variation. If Japan would sanction 18 cruisers for the United States, the latter would defer construction of the last three cruisers respectively until 1934, 1935, and 1936. Ambassador Tsuneo Matsudaira, who came to London from Paris and took the lead in negotiation for a compromise, offered to accept this condition if Japan were allowed 20,000 tons in other categories of warships. To ensure that the Japanese did not get this last concession, Stimson called a meeting of the heads of the three delegations at the Ritz Hotel. There he summarily informed Watasuki that Reed’s offer of 8 March was the final American offer. Further, if the Japanese were unable to accept, Britain and the United States were prepared to exclude Japan from their negotiation. Such an exclusion, he implied, would be disadvantageous to Japan’s naval position.²¹

The so-called Reed-Matsudaira Compromise was arranged on 13 March. Under the arrangement, the United States could construct 14 heavy cruisers between 1930 and 1936. The delay in U. S. construction of its final three cruisers would give Japan a de facto 10:7 ratio until 1936.

Ambassador Castle at once became involved in obtaining approval for this agreement. Through informal meetings, he tried to convince Shidehara that American concessions were fair and that the Japanese had not been asked to make dramatic sacrifices. Castle had also received directions from Stimson to emphasize the impossibility of American compromise. The ambassador chose, however, to stress the fairness of the U. S. proposal rather        than that Japan had virtually no real choice in accepting the final offer. He pointed out that even if concessions were possible, the British would not likely agree. Reluctantly, the Japanese envoys accepted a compromise rather than assume responsibility for failure of the conference.²²

Even before the compromise, proponents of a large navy for Japan had been conducting a campaign to persuade countrymen that America was a potential enemy and that any alterations in Japanese demands would be suicidal. The chief opponent of compromise was the chief of the Japanese naval staff, Admiral Kanji Kato. Referring to the compromise as the American Proposal, he particularly objected to the low ratio in heavy cruisers and prohibition of new submarine construction before 1936. Most Tokyo newspapers echoed his objections.²³ Castle’s strategy was to ignore the press complaints and to concentrate on key officials and Japanese public support.

Castle disagreed with Stimson’s coercive approach. He observed that any sign of U.S. pressure would reduce chances that the proud Foreign Minister or the Premier would support the compromise. Castle decried the earlier threats of an Anglo-American treaty made without regard for Japan’s defense concerns.²⁴ Thus, in realizing that bold threats would weaken the ability to work with civil officials in the Hamaguchi cabinet and realizing that coercion would needlessly test Shidehara’s statesmanship, he facilitated Japanese acceptance of the Reed-Matsudaira Compromise.

Castle was able to report on 3 March that the Hamaguchi cabinet had accepted the compromise and that instructions were to be sent to the delegation in London.²⁵ He believed the key to acceptance had been Shidehara’s political courage and the influential Count Makino’s representations to the Emperor.

Although Stimson in London could report that the Japanese delegation had presented a reply that “amounted to a substantially complete acceptance of the compromise,” Castle worried that acceptance by the privy council would not be automatic. He told Hoover:

All this looks hopeful enough, but it does not take into account the Army and Navy, which are immensely powerful. At the time of the Russo-Japanese war the chiefs of the general staffs were given Cabinet rank so that they might approach the Emperor directly. This rank they have retained, and it makes them less responsible to the Ministers of War and Marine who are technically their chiefs.²⁶

Indeed, before formal Japanese ratification in October 1930, the naval command challenged both acceptance of the treaty and civil control over military affairs. Shortly after acceptance and the treaty’s return for ratification, Castle proved right. Led by Admiral Kato, the naval chief of staff, the opposition party and other nationalist groups argued the following:

The London Treaty would adversely affect the empire’s security.

The proposal came within the “right of supreme command” defined by Article II of the Constitution.

Kato, as a head of the Naval General Staff, bore personal responsibility for exercising this right of supreme command.

Through direct access to the Emperor, he could prevent acceptance of this unsatisfactory treaty.²⁷

The leading form of opposition other than appeal to the "right of supreme command” was to delay consideration by the privy council by insisting that the Diet debate the treaty.

Ambassador Castle knew better than to involve himself directly in Japanese politics and could only report the slow Progress toward ratification. Noting the lack of enthusiasm for the treaty, he guessed correctly that the quicker the ratification the better. In private talks with Shidehara and Hamaguchi, he urged dispatch and claimed that although the treaty represented an imperfect compromise for all three powers represented at London, Japan’s security Would be assured for the duration of the treaty. He avoided the threat of an Anglo-American treaty and stressed the importance of goodwill, cooperation, and the compatibility of Japanese and American interests in China. To give weight to the American position, he urged Senator Reed and Secretary Stimson to set out publicly in the Senate hearings the concessions the United States had made.²⁸

The conflict over ratification in Japan was, as Castle described, bitter because it was a conflict between the military and civil branches of government. After many weeks of opposition between Premier Hamaguchi’s government, which fully supported the treaty, and Kato’s forces, that denied the civil government’s right to determine the size of the fleet, the privy council formally approved the treaty on 1 October. At least temporarily, civil control of foreign Policy had been asserted, and Hamaguchi could announce with Castle that the treaty marked a move forward.

In retrospect, the London Naval Conference proved less of a success than Castle and the Hoover administration thought. That the forces of fanaticism were only beginning to show their strength was made painfully evident when Hamaguchi was assassinated in November 1930.²⁹ The appearance of democracy, which had so impressed Castle, proved illusory. Too, increasing Japanese investment in China seemed to require a big navy. Unrestricted access to China, viewed as the basis of future economic security, drove Japanese expansion. Even as ratification in Japan occurred, the Seiyukai was preparing to maintain Japan’s position in Manchuria along with a foreign policy that denied the need for ongoing cooperation with Britain and the United States.³⁰ A treaty intended to increase the chances for peace produced political unrest, and even galvanized the forces for war.