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Chapter The Origin of the Plan to Attack Singapore 1936-40 In 1936, with the termination of the Washington Treaty and its Article 19, the Imperial Japanese Navy lost its reason to accept the Singapore Naval Base. Furthermore, geopolitical advantages that Japan enjoyed until then were beginning to disappear as a result of the termination of naval disarmament treaties and technological advances. This year, Japan revised the Teikoku Kokubō Hōshin (Imperial National Defence Policy), in which Britain was included as one of its hypothetical enemies. It was the first time in Japanese history that Japan formally regarded Britain as its hypothetical enemy. On 11 May, when Chief of the Army General Staff, Prince Kan’in, and Chief of the Navy General Staff, Prince Fushimi, presented the newly revised Teikoku Kokubō Hōshin, Emperor Hirohito asked: “Why add Britain?” Prince Kan’in replied: “Recently Britain has been hastily strengthening fortifications in Hong Kong and Singapore. Moreover, international relations are not stable. We have to provide against an emergency”. Prince Fushimi added: “As far as the navy is concerned, we consider it is better to avoid a war against Britain. If a war against the Soviet Union should break out, the United States will join the Soviet side. If a war against the United States should break out, the Soviet Union will join the American side. In these cases, China will definitely join 143 our enemy. If Britain also joins our enemy, we stand no chance of winning. On the other hand, if a war against Britain should break out, there will be a high possibility that not only China but also the United States and the Soviet Union will join our enemy. It is better to avoid these scenarios by diplomacy. The reason why we added Britain is to provide against an emergency and no more than that.”1 But five years later, Japan plunged into war against Britain and the United States by attacking British Malaya, the Philippines and Hawaii simultaneously. When considering Japanese policies against Britain in the period between the two world wars, 1936 was an important turning point. On 15 January, the Japanese government announced withdrawal from the London Naval Conference. On 26 February, there was the 26 February Incident, which was an attempted military coup d’état. In the early hours of the morning, soldiers led by radical junior-echelon army officers, attacked government buildings in Tokyo. Several senior politicians were murdered. The Prime Minister, Okada Keisuke, narrowly escaped being murdered. The Emperor, believing the Prime Minister had been killed, ordered the Imperial Japanese Army to suppress them. After the 26 February Incident, Hirota Kōki formed a new cabinet on March. The revision of the Teikoku Kokubō Hōshin was approved on June. On August, the Hirota Government adopted “Fundamentals of National Policy (Kokusaku no Kijun)” in which the BBKS, Senshi Sōsho, Daihon’ei Kaigunbu, Rengō Kantai, 1: Kaisen Made (The Imperial Headquarters, Navy Combined Fleet, Vol. 1, Up to the Outbreak of Hostility), (Tokyo: Asagumo Shinbunsha, 1975), p.325. 144 Japanese government stipulated expansion to both the south and the north. The south-bound policy was officially approved as a national policy. On 25 November, it concluded the German-Japanese Anti-Comintern Pact.2 This chapter examines the Japanese south-bound policies from 1936 to 1940 and the origin of the Japanese plan to attack British Malaya and Singapore. In particular, it analyses the history of two different but related aspects. The first is why the Imperial Japanese Navy proposed the south-bound policy and how it became national policy. The second is the origin of operational plans to attack British Malaya and Singapore made by the Army General Staff and the Navy General Staff. How and when did the Navy General Staff and the Army General Staff make their first operational plans to attack British Malaya and Singapore? It has been widely believed in the English-speaking world that Japan had been preparing to attack British Malaya and Singapore for many years. On the other hand, some historians considered that Japan made the plan to attack Singapore from scratch just before the war.3 Both of these views should be reconsidered. Kiyoshi Ikeda, “The Road to Singapore: Japan’s View of Britain, 1922-41”, in Fraser, T.G. and Lowe, Peter (eds.), Conflict and Amity in East Asia: Essays in Honour of Ian Nish (Basingstoke: Macmillan Press, 1992), p.31 Haruo Tohmatsu, “The Imperial Army Turns South: the IJA’s Preparation for War against Britain, 1940-1941”, in Ian Gow, Yoichi Hirama and John Chapman (eds.), The History of Anglo-Japanese Relations, 1600-2000 Volume Three: The Military Dimention (Basingstoke: Macmillan Press, 2003), p.176; Brian P. Farrell, The Defence and Fall of Singapore 1940-1942 (Stroud: Tempus, 2005), p.107. 145 The Origin of the South-bound Policies The origin of Japanese south-bound military policies can be traced back to 1933. Before that, Japanese south-bound movements did not assume a military tone. As early as the early Meiji period, in the 1870s and 1880s, the Japanese started living as immigrants in Nanyo. The Japanese word Nanyo referred to islands in the south Pacific, and islands and islets in Southeast Asia in the Meiji Period4, but from around the time of the First World War, it was enlarged to refer to islands in the south Pacific and the region that we currently know as Southeast Asia. Soto Nanyo or Omote Nanyo referred to Southeast Asia while Uchi Nanyo or Ura Nanyo referred to islands in the south Pacific.5 After the Russo-Japanese War, some of the leading Admirals, such as Yamamoto Gombei and Satō Tetsutarō, envisaged south-bound advance as future national policy. They considered south-bound advancement would be more beneficial for national defence and development than the army’s north-bound expansion into Manchuria and Mongolia. But their expectations in the south were too vague to be formed into a concrete naval policy.6 During From August 1868 to 30 July 1912. Hajime Shimizu, Southeast Asia in Modern Japanese Thought: Essays on Japanese-Southeast Asian Relationship 1880-1940 (Nagasaki: Nagasaki Prefectural University, 1997), p.4 ; Sumio Hatano, “Kokubō Kōsō to Nanshin-ron (National Defence Policies and South-Bound Policies)”, in Yano,Tōru, Tōnan Ajia to Nihon (South East Asia and Japan) (Tokyo: Kōbundō, 1991), p.149. Kiyoshi Ikeda, “The Road to Singapore: Japan’s View of Britain, 1922-41”, p.35; Ken’ichi Goto, Shōwa ki Nihon to Indonesia (Japan and Indonesia in Shōwa Era) (Tokyo: Keisō Shobō, 1986), p.20; Sumio Hatano, “Nihon Kaigun to Nanshin Seisaku no Tenkai (The Japanese Navy and its Policies to the South” in Shinya Sugiyama and Ian Brown (eds.) Senkan-ki Tōnan Ajia no Keizai Masatsu: Nihon no Nanshin to Ajia Ōbei (Economic Frictions in South East Asia during the Inter War Period: Japanese South-bound Policies, Asia and Western Powers (Tokyo: Dōbunkan Shuppan, 1990), p.142. 146 the Taishō Period7, Japanese companies sought economic expansion in Nanyo. Trading companies and banks established their branches in Singapore. As a result, there was a sharp rise in Japanese exports to the Nanyo region. However, the Imperial Japanese Navy had no military policy for the Nanyo region. From the Japanese point of view, Japanese south-bound advancement did not contradict the colonial policies of Western powers because the Japanese had no intention to overthrow Western interests in Nanyo. It was not until the middle of 1933－after Anglo-Japanese relations were deteriorating in consequence of Japanese military actions in Manchuria in 1931, the Shanghai Incident in 1932, the Japanese proclamation of Manchukuo on March 1932 and the Japanese withdrawal from the League of Nations in 1933－that the Imperial Japanese Navy began to examine a policy of advancing into the south. In September 1933, when a Japan-India-Britain conference on the cotton trade had been deliberating in Simla, which intensified anti-British feeling in the Japanese public, the Minister of the Navy, Ōsumi Mineo, approved a “Guideline dealing with China” which stipulated: “Faced with the military penetration by the powers into the south of China, Japan must be more intensively watchful of them, and try to prevent their aggressive moves. It is now inevitable for Japan to adopt a more active strategy in this area within the very near future.”8 A historian, Ikeda Kiyoshi, pointed out that it was the first formal announcement From 30 July 1912 to 25 December 1926. Ikeda. “The Road to Singapore: Japan’s View of Britain, 1922-41”, p.36; Gendaishi Shiryō (Documents on Modern History), Vol. 8, Nitchū Sensō (Sino-Japanese War 1) (Tokyo: Misuzu Shōbō, 1964), p.10, pp.351-53. 147 of south-ward advance made by the navy. But at that time, south-ward advance meant advance to southern China. There was no military plan for advancing to the Nanyo region. Economic reasons lay behind why the Imperial Japanese Navy aroused interest in Nanyo in the mid-1930s. A historian, Asada Sadao, wrote: “As long as Japan could obtain such resources as petroleum, rubber, and scarce metals through trade with the United States and the western colonial powers in Southeast Asia, the navy did not need to intervene. However, as relations with the United States deteriorated, the navy became increasingly concerned with the possible shortage of petroleum for its fleets and naval aviation.”10 Another historian, Goto Ken’ichi, pointed out that one of the two reasons why the Imperial Japanese Navy did not have a south-bound military expansion policy until the mid-1930s came from its oil supplying policy.11 Since the time of the First World War, the Imperial Japanese Navy’s policy consisted of two parts. The one was a self-support programme and the other was an oil import programme. However, in 1916, it had already become clear that it was impossible to self-support its oil consumption. In 1917, it contracted an agreement with the Anglo Petroleum Company to import oil from Tarakan, Borneo. This contract solved the navy’s oil supply problem. In later years, the contract to import Borneo oil was succeeded by the Asiatic Ikeda, “The Road to Singapore: Japan’s View of Britain, 1922-41”, p.36. Sadao Asada, From Mahan to Pearl Harbor: The Imperial Japanese Navy and the United States. (Annapolis: Naval Institutional Press, 2006), p.207. 11 The other reason was pro-Anglo-American policies pursued by the “treaty faction” of the Imperial Japanese Navy. 10 148 Petroleum Company.12 As long as the import of oil was secure by free trade, it did not require a policy of forcefully capturing oil. In other words, importing oil from Nanyo put the brakes on a naval south-bound military policy until the mid-1930s. What was important for the Imperial Japanese Navy until the mid-1930s was how to secure a stable supply of oil from Nanyo by importation.13 South-bound military advancement to Nanyo was incompatible with this policy. However, as relations with the United States and Britain were deteriorating, importing oil from Southeast Asia became uncertain. To research the Nanyo region, the Imperial Japanese Navy established on 15 July 1935 the Committee to Investigate Southern Policy, with the Vice-Chief of the Navy General Staff, Shimada Shigejirō, as the chairman. Members of this committee consisted of officers of the Ministry of the Navy and the Navy General Staff. Commander Chūdō Kan’ei and Captain Nakahara Yoshimasa proposed establishing this committee to Captain Oka Takazumi and it was established on Oka’s initiative. Chūdō and Nakahara had developed a passionate interest in Nanyo through books and voyages.14 Chūdō realised during a graduate voyage of the Naval Academy to Nanyo in 1916 that only a small number of Western people exploited rich natural resources in undeveloped Nanyo. Consequently, there would be great opportunities for the Japanese to develop industries and foster trade in this region. The Imperial Japanese Navy could back up their activities by financial aid, giving BBKS, Senshi Sōsho: Kaigun Gunsenbi, (Naval Armament and War Preparations, Vol. 19) (Tokyo: Asagumo Shinbunsha, 1969), pp.694-95. 13 Goto, Shōwa ki Nihon to Indonesia, 22-31, pp.83-85. 12 14 Hatano, “Nihon Kaigun to Nanshin Seisaku no Tenkai”, p.149. 149 intelligence, and protecting sea routes. Nakahara, who had a nickname “The King of Nanyo”, shared similar experiences. 15 The main purpose of the committee was to research the oil question. For the first time, the Imperial Japanese Navy began to systematically investigate petroleum resources in the Nanyo region, especially in the Dutch East Indies, in order to prepare for a Japanese-American conflict. The aims of the committee included conducting various surveys and studies of everything related to Omote Nanyo－British Malaya, Borneo, the Dutch East Indies and French Indochina－from the viewpoints of national defence and the national policy relating to it. Commander Nakazawa Tasuku, a member of this committee, was of the opinion that any advance to the East Indies might very well result in a clash with the Anglo-American powers. However, in this committee’s study, as regards an advance on Omote Nanyo, the Imperial Japanese Navy did not necessarily play a primary role, economic expansion or immigration were the basic methods studied.16 In other words, at this stage, Nanshin (South-bound Advancement) to Nanyo did not mean military expansion. After Hirota Kōki formed a cabinet on March, to study and formulate naval policies, the Ministry of the Navy established three new committees on 19 March. Members of these committees consisted of officers of the Ministry of the Navy and the Navy General Staff. Their aim was “to prepare naval armaments that will give confidence in national defence in view Ibid., pp.146-147. Asada, From Mahan to Pearl Harbor, p.207; Kiyoshi Aizawa, “The Path Towards an ‘Anti-British’ Strategy by the Japanese Navy between the Wars”, in The History of Anglo-Japanese Relations, 1600-2000 Volume Three: The Military Dimention, p.142. 15 16 150 of the fact that at the end of this year [1936] naval treaties will expire”.17 Among these three committees, the most important for our purpose was the First Committee. The task of the First Committee was to study and formulate a firm and concrete policy of south-bound expansion. The Second Committee was to study how to make the organisation of the Imperial Japanese Navy more efficient and the Third Committee was to study naval budget and financial affairs. The Chair of the First Committee was Vice-Admiral, Toyoda Seomu, Chief of Naval Affairs Bureau. However, it has been said that the officer who actually dominated the First Committee was Captain Nakahara Yoshimasa who was the foremost exponent of a south-bound advancement within the Imperial Japanese Navy. Policies set forth by the First Committee were summarised in the paper “National Policy Guidelines (Kokusaku Yōkō)” with army’s policies on the continent in April 1936. It stipulated: “The basic policy of imperial national policy guidelines should be to reinforce various policies domestically while securing a foothold for the Empire on the continent and simultaneously expanding southwards”.18 With regard to policy towards the “various southern countries”, it insisted on: Gendaishi Shiryō Dai kan, Nitchū Sensō 1, p.351; BBKS, Senshi Sōsho: Daihon’ei Kaigun-bu, 1. , p.291; Asada, From Mahan to Pearl Harbor, p.207; 18 Gendaishi Shiryō Dai kan, Nitchū Sensō 1, p.354; Aizawa, “The Path 17 Towards an ‘Anti-British’ Strategy by the Japanese Navy between the Wars”, p.142; ; Kiyoshi Aizawa, Kaigun no Sentaku: Saikō Shinjuwan e no Michi (The Navy’s Choice: The Road to Pearl Harbour Reconsidered) (Tokyo: Chūō Kōronsha, 2002), pp.123-24; BBKS, Senshi Sōsho, Daihon’ei Rikugunbu, (Imperial Headquarters, Army, Vol.1, Up to May 1940)’(Tokyo: Asagumo Shinbunsha, 1967), p.381; Ikeda, “The Road to Singapore: Japan’s View of Britain, 1922-41”, pp.36-37. 151 Domestically, a method which will permit unification [of making and execution of policies] should be discussed and determined; and the necessary organisations established, while the administration of Taiwan and the Mandated Islands should be strengthened. Internationally, a gradual expansion should be attempted, for the time being, through increasing immigration and economic expansion, while careful preparations shall constantly be made against pressure or interference from Britain, the United States and the Netherlands, which is naturally to be expected. The completion of preparations of forces, for an emergency, is necessary.19 This paper stipulated increasing immigration and economic expansion as means for Japanese south-bound policies but also anticipated the situation that Britain and the Netherlands would become possible enemies. The United States remained the main target of the naval expansion. 20 The Imperial Japanese Navy’s policies for Britain and the United States were outlined in the National Policy Guidelines as follows: Policies Towards Britain Great caution must be paid to possible action by Britain to use another foreign power, in particular the United States, the Soviet Union or China, to apply pressure on Japan, and we must take advantage, whenever possible, of the delicate political situation in Europe and the political condition in the British colonies in order to expand our national power into the cracks among 19 20 Ibid. Asada, From Mahan to Pearl Harbor, p.207. 152 The Army General Staff sent several officers to Southeast Asia to gather information from 1937 to 1941. Major Imoto Kumao was one of them, but the mastermind of the plan for attacking Singapore. He was in charge of coordinating its Annual Operational Plans with his Navy counterpart, Commander Yamamoto Chikao, and participated in drafting them in 1938 and 1939 when the Operations Sections shaped up their plans for attack. In addition to sending its officers, the Army General Staff gathered information on Southeast Asia from several sources. One source was the Military Attaché’s Office in Bangkok. From there, it gathered information on landing places, airfields and weather in the northern part of the Malay Peninsula. Other information sources were through Japanese Consulates in Southeast Asia and trading companies. The Army General Staff sent officers of the Operations Division or the Intelligence Division to these establishments under cover identities.66 Until September 1941, it gathered maps and related information.67 In the summer of 1940, Chief of Air Group in the Operations Section of the Army General Staff, Lieutenant Colonel, Tanigawa Kazuo travelled to British Malaya and Singapore to gather information.68 From January to March 1941, Kunitake Teruto travelled British Malaya. By August 1941, it became 66 NIDS, Army Documents, Nansē Zenpan 35, “Nanpō Sakusen Heiyō Chishi Shūshū”, , 5-7. This document is Colonel Sugita Ichiji’s reminiscence made for the Military History Department, the Agency of Defence for writing Senshi Sōsho dated on 14 November 1958. He was a staff officer in the Intelligence Bureau. From October 1941, he was a staff officer of the 25th Army. 67 NIDS, Army Documents, Nansē Zenpan 172, “Eiryō Malaya Jōhō Kiroku”. This is a file of maps and related information of the Malay Peninsula and Singapore dated on 20 September 1941. These maps were used by the Operations Section of the Army General Staff during the war. As is well known, the 25th Army lacked maps. 68 BBKS, Senshi Sōsho, Nanpō Shinkō, Rikugun Kōkū Sakusen (Army Air Forces Operations in the South) (Tokyo: Asagumo Shinbunsha, 1970), p.32. 181 extremely difficult to station officers with cover identities. But even after that, two officers, Major Ōsone and a Major from Air Group, remained in the Japanese Consulate in Singora. Major Kagoshima remained in the Japanese Consulate in Singapore, They returned to Japan just before the war.69 In the English-speaking world, there is a prevailing impression surrounding Japanese espionage before the war: Japanese tin mines, pineapple plantations, photo studios, barber shops and bordellos all over Malaya and Singapore were organised in a strategic conspiracy to keep an eye on all military installations and sensitive areas, and every Japanese was part of a well-prepared spy ring.70 As a historian, Brian Farrell, rightly pointed out, “it is wrong, but only because it is exaggerated”.71 There was no clear evidence on the Japanese side that these kinds of Japanese expatriate’ activities contributed greatly for making and conducting operational plans to attack British Malaya and Singapore. What is far more important is that staff officers of the Operations Section travelled Southeast Asia for getting information at first hand. The making of Annual Operational Plans for 1940 was delayed for three reasons. The first reason was the prospect of the course of the Sino-Japanese War. It was not clear at that time. The second reason was the outbreak of the Second World War in Europe in September. And, the third reason was that the Operations Section of the Army General Staff waited for NIDS, Army Documents, Nansē Zenpan 35, “Nanpō Sakusen Heiyō Chishi Shūshū”, 5-7. 70 Farrell, Brian, The Defence and Fall of Singapore 1940-1942 (Stroud: Tempus, 2005), p.135. 71 Ibid. 69 182 Major Imoto to return from Southeast Asia. The “Annual Army’s Operational Plan for 1940” and the “Annual Navy’s Operational Plan for 1940” were presented to the Emperor on 14 December 1939. Results of Major Imoto tour was reflected in the “Annual Army’s Operational Plan for 1940” but how far results of Major Imoto’s trip was reflected in the “Annual Navy’s Operational Plan for 1940” is unclear. When he returned from Southeast Asia, the “Annual Navy’s Operational Plan for 1940” was almost completed. The most notable difference of these plans from those of the previous year was that the operational plan against China and Britain changed to the operational plan against three countries: China, Britain and France. They added military plans for capturing airfields in French Indochina to be used as advanced bases for attacking British Malaya, Singapore and British Borneo.72 Senshi Sōsho, Japanese Official War History Series, explains that the General Staffs supposed at the time that Britain and France were inseparable not only in Europe but also in Asia, so that it was necessary to include plans against France into plans against Britain.73 But this explanation misses an important fact. In fact, Major Imoto considered using airfields in French Indochina even before the outbreak of the war in Europe. He recognised that it was impossible for the Imperial Japanese Army to attack British Malaya and Singapore without advanced bases in southern French Indochina and in southern Thailand. To attack British Malaya and Singapore without the strong support BBKS, Senshi Sōsho: Daihon’ei Kaigun-bu, 1. , pp.466-479; BBKS, Senshi Sōsho: Daihon’ei Rikugun-bu, 2. , pp.11-25. 72 73 Ibid. 183 of the navy, the army required staging bases between Japanese occupied areas in China and British Malaya. The naval operational plan against Britain and France in the “Annual Navy’s Operational Plan for 1940” consisted of two stages. In the first stage, the navy “will annihilate enemy’s fleets and air forces in East Asia and bring East Asian Seas under its control. In cooperation with the army, it will attack Hong Kong, French Indo-China, British Borneo and key areas in the British Malay Peninsula. After that, it will occupy or attack Singapore”. In the second stage, the navy “will await the British main fleet coming to East Asia and annihilate it. If the British main fleet is stationed in Indian or Australian water to extend a war, the navy will endeavour to bring the enemy out by diminishing the enemy’s forces and destroying its transport capability and will bring the Western Pacific and its air space north of the equator under its control. By these means, the navy will strengthen its strategic condition”. In the first stage of this war plan, it planned to use a fleet consisting of the Second Fleet and the Third Fleet for operations in the South China Sea. The operation plan for these fleets was: (1) At the opening stage of operations, it will capture and annihilate enemy’s fleet and air forces stationed in East Asia. (2) At the opening stage of operations, it will escort the army, and in cooperation with the army, it will make surprise attacks against key areas in French Indochina and British Borneo, annihilate enemy forces and their bases, and capture advanced bases and airfields. Then it will 184 attack Singapore and key areas surrounding Singapore by air forces. (3) Army’s landing places in French Indo China will be: main forces in the coastal areas south of Saigon, a part of the forces in Da Nang. At the opening of hostilities, the Army will advance a part of its forces to the Hanoi plains areas from Lang Son. (4) Army’s landing places in British Borneo will be Kuching, Brunei, Labuan and Jesselton. (5) After operations in French Indo-China and British Borneo, it will escort the army which will land in Mersing, attack Singapore and occupy key areas surrounding Singapore. Before that, it will escort the army to land in north-east of British Malaya to made operations by main forces easier. If conditions allow, it will land in Singora in Thailand. In the second stage, the Third Fleet will be stationed in British Borneo and Singapore areas, protect these areas and support main operations of the Combined Fleet by reconnaissance.74 In the operational plan against China, Britain and France in the “Annual Army’s Operational Plan for 1940”, it assigns Kō Detachment which consists of four battalions for attacking British Borneo and the 15th Army which consists of two divisions for attacking the Malay Peninsula and Singapore. For attacking French Indochina, it assigns the 16th Army which consists of two divisions. The operations plans for the 16th Army in the French 74 BBKS, Senshi Sōsho: Daihon’ei Kaigun-bu, 1. , pp.474-477. 185 Indochina theatre were: (1) At the beginning of hostilities, it will advance one corps to Hanoi plains from Lang Son and occupy areas surrounding Hanoi. One detachment will land at Da Nang, occupy airfields and break off enemy’ communications between Hanoi areas and Saigon areas. (2) It will land one other corps in the coastal areas south of Saigon, occupy the areas surrounding Saigon and occupy Cam Ranh Bay as soon as possible. Note. It will conduct these operations in cooperation with the navy.”75 The operation plans for Kō Detachment and the 15th Army for attacking in British Borneo and Singapore theatre were: (1) After commencing operations of the 16th Army, Kō Detachment will land in key areas of British Borneo viz., Kuching, Brunei, Labuan and Jesselton, and develop airfields and occupy key areas which surround them. (2) As soon as operations of the 16th Army and Kō Detachment are complete, the 15th Army will land in Mersing, attack Singapore from land side and occupy key areas surrounding it. It will land one corps in northeast British Malaya to make operations of main forces easier. 75 BBKS, Senshi Sōsho: Daihon’ei Rikugun-bu, 2. , p.21. 186 If conditions would allow, it will land in Singora in Thailand. Note. It will conduct these operations in cooperation with the navy.”76 Singora was still the first choice for the Operations Sections as the landing site. They followed the phrases of the previous year, which were finally accepted by the Emperor. It was not clear where “northeast British Malaya” was. But, it is very likely that “northeast British Malaya” was an alternative to Singora. When the Operations Sections made these plans, they could not specify where a suitable landing site was in northeast British Malaya. Imoto did not visit Kota Bahru during his trip. Compared with Annual Operations Plans of the previous year, it added operational plans in French Indochina, and specified landing sites in British Borneo, but withdrew a plan to land small forces directly on Singapore. When Prince Kan’in and Prince Fushimi presented their annual operational plans for 1940 to the Emperor on 14 December 1939, Prince Kan’in explained the British and French estimated defence forces to the Emperor. “The regular Army forces stationed in Singapore are five battalions infantry, eight companies artillery and three hundred aeroplanes. The volunteer Army are ten battalions infantry. We got information that after the outbreak of the war in Europe, 7,000 additional forces arrived from India. In case of war, we not consider that defence forces of Hong Kong will increase but it is necessary for us to suppose that defence forces of Singapore will increase. We 76 Ibid., pp.20-22. 187 assume defences of Singapore are reinforcing but we not know the details. There are a small number of guards in British Borneo but it is almost undefended.”77 As for the number of aeroplanes, the Army General Satff overestimated the number stationed in Singapore. At that time, the number of British aeroplanes in British Malaya, including Singapore, was fewer than ninety.78 As we saw above, the “Annual Army’s Operational Plan for 1940” and the “Annual Navy’s Operational Plan for 1940” added operational plans to capture French Indochina. The Operations Sections planned to use French Indochina as advanced bases for attacking British Malaya and Singapore. By adding operational plans in French Indochina, operational plan to attack Singapore became three stage plans. First, it would capture air bases in French Indochina as advanced bases for attacking the Malay Peninsula. Second, it would land army’s land forces in Mersing, northeast of British Malaya or Singora, Third, it would advance the Malay Peninsula and attack Singapore from the landing site. The “Annual Navy’s Operational Plan for 1941” which was presented to the Emperor on 17 December 1940 is missing. Only the “Annual Army’s Operational Plan for 1941” which was presented to the Emperor on 24 December exists. That year, the Army General Staff and Navy General Staff presented their Annual Operational Plans to the Emperor severally. There were Ibid. , p.20. W. David McIntyre, The Rise and Fall of the Singapore Naval Base, 1919-1942 (London: Macmillan Press, 1979), p.169. 77 78 188 two distinctive feature of the army’s operational plan against Britain in the “Annual Army’s Operational Plan for 1941”. The first was that the Army General Staff made it on the assumption that it would use southern French Indochina and Thailand as advanced bases.79 The second was that the war plan against China, Britain and France changed to the plan against China, Britain and the Netherlands. Japan had already advanced to northern French Indochina in July that year and the Army General Staff regarded Britain and the Netherlands as inseparable. 80 “The operational policy of the Imperial Japanese Army against Britain and the Netherlands was that, in cooperation with the navy, it will attack Hong Kong and Singapore and occupy key areas in British Borneo, Sumatra and Java.” Notable differences from the operational plans of the previous year were that the Operations Sections made them on the assumption that French Indochina was changed from its enemy to its ally and Thailand was not a neutral country: it would be either a Japanese ally or a British ally. Therefore, it no longer cared whether landing a force in Singora and Patani would breach its neutrality. The number of divisions composing the 15th Army enlarged to four divisions. As for landing places of main forces, it became more definite than the previous year: Singora, Patani and Kota Bahru. The Annual Operational Plan of the previous year stipulated “north-east of British Malaya” as one of the landing sites, but this year, it specified the landing site in north-east of British Malaya as Kota Bharu. The reason why the Operations Section chose Singora, Kota Bharu and Patani as 79 80 BBKS, Senshi Sōsho: Daihon’ei kaigunbu: Rengō kantai, 1, p.506. BBKS, Senshi Sōsho: Daihon’ei Rikugunbu, 2, p.159. 189 landing sites was operational needs of the Army air forces. Landing these places was suitable for capturing British airfields in Kota Bharu and Kedah Province. Lieutenant-Colonel, Tanigawa Kazuo travelled British Malaya in July and early August 1940 to gather information related to air operational plans. The operational plan for the 15th Army was: (1) At the beginning of hostilities, the 15th Army’s air forces flying from Southern French Indochina, in cooperation with the navy, will annihilate enemy’s air forces stationed in Malay. Before that, it will develop airfields in advance in French Indochina. Detailed plans for this to be made depending on situations. (2) In early stages, after the commencing of hostilities, in cooperation with the navy, it will land advanced units in Singora, Kota Bharu and Patani, occupy and develop airfields. One Air Squadron will advance to these places, defeat enemy’s air forces and backup our (land) operations thereafter. (3) The main forces of the 15th Army will land in Singora and advance southward for Singapore along west coast of the Malay Peninsula. During these operations, it will land one squad, in cooperation with the navy, in Mersing, east coast of the Malay Peninsula, to expedite operations. After that, the 15th Army will attack Singapore from landside and occupy key areas surrounding it thereafter. One squad will stand by in French Indochina. It will use these forces wherever it will 190 become necessary.”81 The “Annual Army’s Operational Plans for 1941” and the “Annual Navy’s Operational Plans for 1941” were the last operational plans before the war. Imperial General Headquarters made the actual operational (war) plan based on them in the autumn of 1941. Some historians believe that Japan made the operational plan to attack British Malaya and Singapore from scratch in the autumn of 1941. But it is wrong and impossible. Even though the Operations Sections started studies for making operational plans against Britain since Britain was included in the hypothetical enemies list of the Teikoku Kokubō Hōshin of 1936, it took more than two years for them to make their first plans to attack British Malaya and Singapore. There was no description of how to attack and how many forces would require for attack in Annual Operational Plans for 1937 and 1938. Conclusion Japan formally included Britain as one of its hypothetical enemies by the revision of the Teikoku Kokubō Hōshin in 1936. In this year, the Hirota Government approved south-bound expansion as national policy officially by the approval of the “Fundamentals of National Policy”. It stipulated expansion towards both north and south. However, it is wrong to consider that these 81 Ibid., pp.153-165. 191 policies led Japan directly to attack British Malaya and Singapore in 1941/42. South-bound expansion stipulated in the “Fundamentals of National Policy” was south-bound expansion by economic means. It is true that there was anxiety within the Imperial Japanese Navy that, if Japan would advance economically, there was a possibility that Japan would be opposed by Britain. However, it was no more than a remote possibility. Even though there were several radical officers who considered Britain as a threat, the dominant view of the Imperial Japanese Navy did not regard Britain as a direct threat. In fact, all the proposals by radical officers which regarded Britain as a threat were rejected by their superiors. Until the mid-1930s, the Nanyo region was one of the most important sources of importing oil for the Imperial Japanese Navy. However, as relations with the United States and Britain deteriorated, the Imperial Japanese Navy started considering that importing oil from the Dutch East Indies would become difficult. Consequently, it started investigating petroleum resources in the Nanyo region in 1935. This led the Imperial Japanese Navy to propose south-bound economic advancement policies in 1935/36. But the direct reason why the Imperial Japanese Navy proposed south-bound policies at that time was to counter the army’s north-bound policy. There arose strong anxiety within the Imperial Japanese Navy that, if it did not propose a counter plan against the army which advocated priority on strengthening Manchukuo and preparations for war against the Soviet Union than naval armaments, the navy could not strengthen its armaments corresponding to the post naval disarmament treaty era. To strengthen its armaments, it required a suitable 192 budget. Proposing south-bound policies became a convenient excuse for the navy to secure its budget. This was how south-bound expansion was approved as national policy in the “Fundamentals of National Policy”. The navy’s south-bound policy in 1935/36 was not war-minded, but budget-minded policy. It also came from sense of rivalry against the army. What is important is that, even though the Imperial Japanese Navy proclaimed south-bound economic expansion and started regarding Britain as one of its hypothetical enemies, the target of naval armaments was still the United States Navy. Since Britain was included on Japan’s hypothetical enemy list in the Teikoku Kokubō Hōshin, the Operations Sections of the General Staffs started making operational plans against Britain. However, they could not complete a substantial operational plan until 1939. The origins of Japanese plans for attacking British Malaya and Singapore were operational plans included in the “Annual Army’s Operational Plan for 1939” and the “Annual Navy’s Operational Plan for 1939”. These plans arouse our interest on the following three points. First, from the very beginning, the Japanese considered attacking Singapore from the land side. To attack British Malaya, they chose Singora in southern Thailand as their landing site. After landing in Singora, Japanese forces would advance down the Malay Peninsula and attack Singapore from the land side. It was quite obvious for the army that, considered with Singapore’s coastal defence, attacking Singapore from the sea side was impossible. Second, in these plans, the main forces for attacking British Malaya and Singapore were the army’s land forces. The navy only took a supportive role by convoying army’s forces to landing sites. Third, they 193 considered extensive use of air forces, mainly army’s air forces, for pre-emptive attacks and covering operations of land forces. Basically, the attack plan for British Malaya and Singapore was designed as the army’s operational plan. The Operations Sections of the General Staffs refined their operational plans in the “Annual Army’s Operational Plan for 1940” and the “Annual Navy’s Operational Plans for 1940”. They added plans for capturing air bases in southern French Indochina as advanced bases for attacking the Malay Peninsula in view of the fact that the army’s air forces could not advance directly to the Malaya Peninsula. It needed staging bases between occupied areas in China and British Malaya. For refining its operational plan, the Operations Section of the Army General Staff sent Major Imoto Kumao, an officer who actually participated in drafting its plans in 1938 and 1939, to Southeast Asia to gather information. By the end of 1940, the Operations Sections refined their plans to attack British Malaya and Singapore once again in the “Annual Army’s Operational Plan for 1941” and the “Annual Navy’s Operational Plan for 1941”. Some historians believed that Japan made its operational plans for attacking British Malaya and Singapore from scratch in the summer of 1941.82 However, this view is incorrect. It was impossible to make them from scratch in such a short time. Even though Britain was included in the hypothetical Tohmatsu, “The Imperial Army Turns South: the IJA’s Preparation for War against Britain, 1940-1941”, p.176; Farrell, The Defence and Fall of Singapore 1940-1942, p.107. 82 194 enemy’s list in the Teikoku Kokubō Hōshin, it took more than two years for the Operation Sections to make their first plans to attack British Malaya and Singapore. Operational plans against Britain in Annual Operational Plans for 1937 and 1938 were “Operational Plans” without any substantial operational plan. There was no description of how to attack and how many forces would be required for attacking. This fact also tells us one important thing. The Japanese armed forces did not consider even a remote possibility of waging war against Britain before 1936. If they had considered, they could have made operational plans to attack British Malaya and Singapore earlier. What Imperial General Headquarters did in the autumn of 1941 was that it refined and integrated operational plans for each operations theatre as an integrated war plan. Most of operational plans integrated in it were already prepared in the “Annual Army’s Operational Plan for 1941” and the “Annual Navy’s Operational Plan for 1941”. The most important exception was operational plan for attacking Pearl Harbour in Hawaii. This was made by the Combined Fleet from scratch in 1941. But the operational plan for attacking British Malaya and Singapore was not an exception. However, making operational plans by the Operations Sections of the General Staffs and the political decision to implement them were different. Until German domination of Low Countries and France in June 1940, the Imperial Japanese Army and Imperial Japanese Navy did not examine a possibility of attacking British Malaya and Singapore seriously. But, what is interesting is that the Operations Sections considered using Singora in Thailand and French Indochina as advanced bases before political decisions 195 for using these places. In other words, to attack British Malaya and Singapore, Japan would have to capture advanced bases in southern French Indochina and Thailand in advance. Otherwise Japan could not implement its operational plans. 196 [...]... consisted of the Prime Minister, the Minister of Foreign Affairs, the Minister of Finance, the Minister of the Navy and the Minister of War It was the famous “Fundamentals of National Policy (Kokusaku no Kijun)” which stipulated expansion towards both the south and the north.27 This showed the fact that the government could not co-ordinate the contradictory policies of the Imperial Japanese Navy and the. .. member of the Operations Section of the Navy General Staff and the navy’s representative to the group that actually drafted the revisions of the Teikoku Kokubō Hōshin, pointed out five reasons why they added Britain to the hypothetical list: (1) Britain contributed greatly to Peace in the Far East by the Anglo -Japanese Alliance for a long time, from 1902 to 1921 However, with the conclusion of the Washington... abrupt change of atmosphere among the younger generation of naval officers Advocates of South-bound Policies In 19 36, Commander Ishikawa Shingo, then a staff officer of the Second Fleet, made a fact-finding tour to Europe On his way to Europe, he visited the Philippines, Java, Sumatra and Singapore In the summer of 1 941, he took a leading role to establish a consensus among middle-echelon naval officers... that there were many well-surfaced roads which connected the main road and the road which ran parallel to the coast of the Malacca Strait From the journalist, he heard that Britain was strengthening the coastal defences of Singapore and there were rumours that Britain had placed naval mines .61 He arrived in Singapore on 11 September In Singapore, he took his every move into consideration He explained to. .. Kan’ei They entered the Imperial Japanese Navy in the 1910s and spent junior officers’ years at sea in the 1920s They might be influenced by anti-Anglo-American public opinion in the 1920s outside of decision making processes of the navy In the 1930s, these officers started working in the Ministry of the Navy or the Navy General Staff as junior or middle echelon officers Traditionally, the Imperial Japanese. .. included in the “Annual Navy’s Operational Plan for 1939”, the navy conducted it before presenting the plan to the Emperor The Commander of the Blue fleet was the Commander-in-Chief of the Combined Fleet, Vice-Admiral Yoshida Zengo, and Vice-Admiral Takasu Shirō took on the role of the Commander of the Red fleet The Red fleet stationed itself near the Andaman and Nicobar Islands and tried to protract the war... Russia (the Soviet Union), and China The Imperial Japanese Army regarded the Soviet Union and China as its hypothetical enemies while the Imperial Japanese Navy regarded the United States as its hypothetical enemy The listing of Britain as one of the hypothetical enemies alongside the Soviet Union, the United States and China in the 19 36 revision of the Teikoku Kokubō Hōshin was undertaken on the initiative... under the strong influence of Britain and the Royal Navy By the mid-1930s, however, younger naval officer’s views of Britain became more similar to those of ordinary Japanese With the adoption of several policies in 1935 and 19 36, the Imperial Japanese Navy’s south-bound advance policies entered a new stage With the introduction of “Fundamentals of National Policy”, the south-bound policy became official... Hainan Island Because of the outbreak of the Sino -Japanese War, the Operations Sections could not make their Annual Operational Plans for 1938 during 1937 Without any perspective on the course of the Sino -Japanese War, they could not establish any plan Since January 1938, after the protraction of the Sino -Japanese War became clear, Commander Yamamoto Chikao from the Operations Section of the Navy General... Ibid 173 the Imperial Japanese Army and the Imperial Japanese Navy greatly affected their operational plans to attack British Malaya and Singapore The Operations Sections of the Army General Staff had to design it as the army’s operational plan without expecting strong support from the navy Considering the coastal defence of Singapore, it was totally impossible for the army to land directly on Singapore . The Origin of the Plan to Attack Singapore 19 36- 40 In 19 36, with the termination of the Washington Treaty and its Article 19, the Imperial Japanese Navy lost its reason to accept the Singapore. chapter examines the Japanese south-bound policies from 19 36 to 1940 and the origin of the Japanese plan to attack British Malaya and Singapore. In particular, it analyses the history of two different. Committee to Investigate Southern Policy, with the Vice-Chief of the Navy General Staff, Shimada Shigejirō, as the chairman. Members of this committee consisted of officers of the Ministry of the