Aung fled first to China and then to Tokyo, where he arranged with the Japanese to create a military force known as the Burmese Independence Army (BIA) to aid the Japanese in their impending invasion of Burma. During the actual battle, which began with the invasion on 14 December 1941 and continued into the next summer, Aung's BIA provided the Japanese with intelligence and logistical support. Aung received the rank of major general in the Japanese army.
Japanese forces overran Rangoon in March 1942. In August 1943 Japan gave Burma nominal independence, and Aung served in the new government as minister of defense. He soon became disillusioned with the Japanese military government, and in August 1944 he formed the Anti-Fascist League of Burma and secretly worked against the Japanese. On 27 March 1945, as Allied forces advanced into Burma, his army switched sides and joined the British.
Allied forces took Rangoon in June 1945. When the Japanese surrendered in August, Aung began negotiations with the British for Burmese independence, his true goal. This effort culminated in an agreement between British Prime Minister Clement Attlee and Aung San on 27 January 1947 that promised an independent Burma in one year. Facing Communist opposition, Aung's party won a large majority in the April 1947 elections.
On 19 July 1947, Aung was assassinated along with six other political leaders. U Saw, Aung's rival for power, was blamed for the assassination. Aung's daughter, Aung San Suu Kyi, later became a political figure in Burma.
Allen, Louis. Burma: The Longest War, 1941–1945. New York: St. Martin's Press, 1984.