https://alphahistory.com/vietnamwar/japanese-occupation-of-vietnam/
Japanese occupation of Vietnam
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The French surrender at home weakened the French colonial government in Vietnam, which had little option but to concede to Japanese demands. An agreement signed in June 1940 allowed Japanese troops to control the northern border between Vietnam and China. Another, signed in August, acknowledged Japans rights and interests in south-east Asia.
Between 1941 and 1945, French colonial authorities in Vietnam, led by Decoux, engaged in a policy of co-existence with the Japanese. Decouxs administration mirrored the Vichy regime that governed occupied France in collaboration with the Nazis.
The Japanese made some effort to win the hearts and minds of the Vietnamese a policy that differed from their brutality and oppression in China. Propaganda suggested the Japanese were in Vietnam as liberators rather than conquerors. Japanese language courses were organised in large cities. Japanese films, literature and poetry were translated into local languages. The Vietnamese people were told how Japans military supremacy was slowly driving the white imperialists out of Asia.
The Japanese presence in Vietnam also attracted foreign attention, particularly from the United States. In 1940, America was not yet at war with Japan but it was still working to restrict Japanese expansion through Asia. The US also wanted to protect its imports of raw rubber, half of which came from Vietnam. ...