The Japanese Period in Indochina and the Coup of 9 March 1945

For the greater part of the period from 1940 to 1945, French Indochina occupied a peculiar place in the Co-Prosperity Sphere of Great East Asia. Following the capitulation of France before the German army in June 1940, the northern part of Indochina became the first area in Southeast Asia to admit Japanese troops — at that stage, as an extension of the Japanese campaign in southern China. In July 1941 the Japanese advance into southern Indochina marked the first step towards a full-scale attack on European and American possessions in the whole region, which materialized in December 1941. But this military advance into Indochina, precisely because it took place before the general assault on Southeast Asia and the Pacific, had to be achieved by means of agreements and treaties with an established government. These were possible only because the French in Indochina decided to recognize the pro-German government at Vichy, so that the Japanese were able to apply diplomatic pressure both in France and at Hanoi. Once the agreements had been made, the Japanese saw no need to change the basis of their occupation of Indochina even after December 1941; they were by then preoccupied with establishing their presence in other areas. Consequently they continued to recognize the French administration in Indochina and to maintain diplomatic relations with it, so long as diplomatic pressure was sufficient to ensure that Japanese military needs were fully met.