Acknowledgements It is my great pleasure to express my gratitude for people who supported me while preparing this thesis. If there is something good in this thesis, it is due to their help while all mistakes and shortcomings are entirely mine. First and foremost, my greatest debt is to my supervisor, Associate Professor Brian Farrell. He gave me invaluable comments and suggestions since I first sent him an e-mail from Japan five years ago. I would also like to express deep gratitude to my co-supervisors: Associate Professor Teow See Heng and Associate Professor Malcolm Murfett. At various stages, they gave me encouragements, support and advices. I am grateful to Mr. Peter Lugg for proof-reading this thesis, to Ms Kelly Lau, a management officer of Department of History, for giving me help and support since I came to Singapore, and to Professor Hirama Yōichi and Associate Professor Ito Shinya for kindly replying to my questions via e-mails. Thanks are also due to my friends in Singapore. Without them, it was impossible for me to complete this thesis. In particular, I wish to convey thanks to Zhang Jing, Orihara Minami, Grace Mak, Hu Wen, and Ho Chi Tim. I would like to express my gratitude to librarians and archivists of following libraries and archives in Japan, Britain and Singapore: the Library of the National Institute of Defense Studies of the Japanese Ministry of Defense, the Diplomatic Record Office of the Ministry of Foreign Affairs of Japan, the National Diet Library, libraries of the University of Tokyo, the Library of National Showa Memorial Museum, the Library of National Defense i Academy in Yokosuka, the National Archives in Kew, the Library of the National Maritime Museum in Greenwich, and the Central Library and the Chinese Library of National University of Singapore. In particular, I would like to mention Mr. Kitazawa Noritaka, a former archivist of the Library of the National Institute of Defense Studies, who helped me to locate documents which I needed, and Ms Tham Wai Fong, a librarian of the Chinese Library of National University of Singapore, who always gave me support and help. My study in Singapore and researches in Japan and Britain was supported by NUS Research Scholarship. Without this scholarship, it was impossible for to complete this thesis. YAMAMOTO FUMIHITO ii Table of Contents Acknowledgements i Summary vi List of Abbreviations viii Introduction Historical Background Previous Studies 13 Japanese Military Organisations 29 Chapter Japan, Britain, the Singapore Naval Base and Naval Disarmaments 1921-36 35 Preparation for the Washington Conference 36 The Washington Conference and the Article 19 of the Washington Treaty 43 The Aftermath of the Washington Conference 56 The London Naval Conference and the Tōsuiken Kanpan Commotion To the abrogation of Article 19 Conclusion 70 77 85 iii Chapter The Singapore Naval Base and the Japanese Public 90 The First Perceptions of the Singapore Naval Base Cancellation of the Plan 94 100 Anglo-Japanese Diplomacy over the Singapore Naval Base 106 The Singapore Naval Base in the Japanese Public in the late 1920s 112 The Vogue of War Scare Literature and the Singapore Naval Base 121 The Singapore Naval Base in Anti-British Movements Conclusion 131 140 Chapter The Origin of the Plan to Attack Singapore 143 The Origin of the South-bound policies Revising Teikoku Kokubō Hōshin Advocates of South-bound Policies 146 157 160 Evolution of Operation Plans to Attack Singapore 1936-1940 Conclusion 165 191 iv Chapter The Road to Singapore 197 Influence of the European War on Japan 198 The Road to the War 227 The Army’s Preparations to Attack Singapore 251 Conclusion 267 Conclusion 272 Bibliography 293 Appendices 320 Maps 326 v Summary The British government decided to establish the Singapore Naval Base to defend its Eastern Empire from Japan in June 1921. Until 1939, however, Japan did not have any plan to attack British Malaya and Singapore. Throughout the period between the two world wars, the Japanese Navy did not examine seriously any plan to attack Singapore from the sea side. The origin of the plan to attack British Malaya and Singapore was an operational plan against Britain included in the “Annual Army’s Operational Plan for 1939” designed by the Japanese Army. In this plan, the Japanese Army would land in Singora in southern Thailand, go down the Malay Peninsula, and attack Singapore from the land side. From the very beginning, the Japanese Army considered attacking Singapore from the land side. From the Washington Conference in 1921/22 to 1936, the Japanese Navy had a unifying view on the Singapore Naval Base. It was not desirable but acceptable on the condition that Britain agreed to Article 19 of the Washington Treaty which prohibited the United States from establishing naval bases in Guam and the Philippines. For the Japanese Navy which regarded the United States as its only hypothetical enemy, prohibiting American bases in Guam and the Philippines was far more important than the British Singapore Naval Base. With the termination of the Washington Treaty, the Japanese Navy lost its reason to accept the Singapore Naval Base in 1936. In 1939, the Japanese Army drew up its first substantial operational plan to attack British Malaya and Singapore. However, it was not until vi Germany dominated European continent in May and June 1940 that the Japanese Army examined a possibility of attacking Singapore seriously. Mesmerised by the German Blitzkrieg, the Japanese Army turned its eyes to the south for the first time in its history. For the Japanese Army, which had regarded the Soviet Union as its principal hypothetical enemy, it was a complete turnabout in its policy. It supposed that it could capture natural resources areas in Southeast Asia concurrent with German attack on Britain. But Britain drove the Germans back by the Battle of Britain. The traditional policy of the Japanese Army against the Soviet Union revived when the Germans launched Operation Barbarossa against the Soviet Union on 22 June 1941. Suddenly, a great chance to attack the Soviet Union came. Accordingly, the Japanese Army mobilised its force to Manchuria to prepare war against the Soviet Union. But on August, the Japanese Army judged that it would be impossible to finish war against the Soviet Union by the coming winter. Rather, it would be better to use the coming winter to capture natural resources in the south to prepare war against the Soviet Union which, the Japanese Army supposed, might happen in the spring of 1942. The primary reason why the Japanese Army considered it would be necessary to attack British Malaya and Singapore was to capture natural resources the Japanese Army needed to prosecute war against the Soviet Union. vii List of Abbreviations BBKS: Bōeichō Bōei Kenshūjo Senshibu (The Military History Department, the Agency of Defence), Japan. DRO: Diplomatic Record Office, the Ministry of Foreign Affairs, Japan. MOFA: The Ministry of Foreign Affairs, Japan. NIDS: Library, the National Institution of Defense Studies, the Ministry of Defense, Japan. NGB: Nihon Gaikō Bunsho (Japanese Diplomatic Documents Series) TNA: The National Archives, Kew, UK. viii . and the Japanese Public 90 The First Perceptions of the Singapore Naval Base 94 Cancellation of the Plan 100 Anglo -Japanese Diplomacy over the Singapore Naval Base 106 The Singapore Naval. Britain and Singapore: the Library of the National Institute of Defense Studies of the Japanese Ministry of Defense, the Diplomatic Record Office of the Ministry of Foreign Affairs of Japan, the National. attack Singapore from the land side. From the very beginning, the Japanese Army considered attacking Singapore from the land side. From the Washington Conference in 1 921 / 22 to 1936, the Japanese