thinking and policies of the Japanese Armed Forces towards the Dutch East In- dies from tint period until 1945, and will attempt to discuss the essential themes. The majority of the materials used in this paper are to be found amongst the offi- cial documents in the Military History Department of National Defense College, and the remaining materials are the records of interviews given by Japanese Army and Navy high-ranking officers.
Growth of Interest
On 7 August 1936 the Japanese Five Ministers' Conference (consisting of Prime Minister Hirota, Foreign Minister Arita, War Minister Terauchi, Navy Minister Nagano and Finance Minister Baba) adopted the 'Fundamentals of Na- tional Policy'. This stated that "we plan to develop nationally and economically vis-à-vis the Southern areas, especially the outer Southern area... We plan to expand our power by gradual peaceful means". The phrase "outer Southern area" meant the islands to the south of Japan's existing mandated islands, with the Dutch East Indies as the essential focus-point. Much importance was attached to the 'Fundamentals of National Policy' in the Judgment of the International Mili- tary Tribunal for the Far East, which saw it as showing Japan's aggressive inten- tions, and it was one of the reasons for Prime Minister Hirota being the only civilian sentenced to death, but, actually, at that point of time, there was no great difference between this policy and Meiji era policies. 4
With the change of warships' fuel from coal to oil and the development of aircraft, the guarantee of oil supplies became an important problem for the Japa- nese Armed Forces, and this factor became the major reason for the Japanese Armed Forces to start paying attention to the Dutch East Indies. After the 1920s tie majority of Japan's oil imports came from America, and, secondly, from the Dutch East Indies. However, as Japan advanced on the Chinese mainland the antagonism between America and Japan gradually increased, and, in inverse proportion, Japan's interest in the Dutch East Indies deepened. America's an- nouncement on 26 July 1939 of her intention to abrogate the United States - Japanese Commerce and Navigation Treaty marked the turning-point for the Japanese Armed Forces to direct their attention closely to the Dutch East Indies. Namely, in the event of America prohibiting the export of oil to Japan, nowhere except the Dutch East Indies could be considered as a possible source of oil for Japan.
With Germany's attack on Poland the Second World War began, and the Japanese Armed Forces watched for the fate of the Netherlands proper. Although the Dutch Government adopted a policy of neutrality, it was thought that there was a strong possibility that this neutrality would be violated either by Britain and France or by Germany. The Japanese Armed Forces were concerned about the fate of the Dutch East Indies if Holland were to be invaded. This concern increased considerably as, with Germany's invasion of Norway and Denmark on