After the occupation of Holland by the German Army and the exile of the Dutch Government to London, Japan wanted to increase her power of influence in the Dutch East Indies and to obtain the necessary strategic materials, oil, rub- ber and tin, by earnest negotiation with the Governor of the Dutch East Indies. The negotiations from September 1940 to June 1941 were conducted by first- rate individuals, firstly, Minister of Commerce and Industry Kobayashi Ichizo, and, secondly, former Foreign Minister Yoshizawa Kenkichi, who were sent to Batavia as the Japanese representatives. The Japanese Armed Forces enthusiasti- cally supported the Japanese Government. However, the Dutch East Indies Gov- ernment, in secret contact with both America and Britain, did not accept readily Japan's demands. This Government, taking the delivery of strategic materials to Japan to mean in effect, with the conclusion of the Tripartite Pact, handing over the rubber and other materials to Germany, adopted a tough line.7 The conclu- sion of the Tripartite Pact, which incorporated Japan's desire to preserve the East Indies within her sphere of influence, in fact had the opposite effect, for it pulled the Dutch East Indies away from Japan.
Disappointed with the Dutch East Indies Government's firm attitude, on 17 June 1941 the Japanese Government broke off the negotiations, and on 28 July sent the Japanese Army into the southern part of French Indo-China. There were various motives for this occupation,8 but the main reason was the Japanese Armed Forces' assessment that there was a likelihood that the East Indies Gov- ernment would be cowed by the Japanese Army's occupation and would conse- quently relax their tough attitude towards Japan. A document prepared by the Imperial Headquarters on 23 June 1941, entitled 'Reasons for the Absolute Ne- cessity, Militarily, Economically and Politically, to Station without delay the Required Troop Strength in Southern French Indo-China in the same way as in Northern French Indo-China', stated that 'there is the prospect that the Imperial advance into southern French Indo-China will contribute to the reopening of the Japanese-Dutch negotiations'.9 One high-ranking member of the Naval General Staff has testified that 'we thought that Holland, ruled by only a Queen, would bow before military pressure.'10 It is clear that the Japanese Armed Forces in their thinking miscalculated the determination of the Europeans in the Dutch East Indies Government to try to resist, as one with America and Britain, Japa- nese pressure.
As is well-known, the American response to Japanese troops entering southern French Indo-China was to break off economic relations with Japan; the Dutch East Indies Government, together with Britain, followed suit. Over a long period of time Japan, particularly the military, had endeavoured to store oil, but it was estimated that, if imports of oil could not be obtained from America and the Dutch East Indies, oil supplies would be exhausted in two years even in peace time, and the mechanised branches of the military would stop moving. Being an island people with plentiful energy, it was a weak point of the Japanese that they could not patiently await the passing of time, trusting the State to the