
This further strained relations between the Bamar ethnic majority and the country's many ethnic minorities. However, Aung San was assassinated shortly afterwards, and the Panglong Agreement was not honoured by the post-independence government under U Nu. The agreement promised full autonomy for the areas inhabited by the three ethnic minorities, with an option to secede from Burma ten years after independence. In the lead up to Burmese independence, Aung San negotiated with Chin, Kachin, and Shan leaders, and the Panglong Agreement was reached between them. Japanese forces capitulated by July 1945, and the British began to negotiate Burma's independence with Aung San and other prominent Burmese leaders. Aung San, the leader of the State of Burma and one of the Thirty Comrades, became increasingly sceptical of Japan's ability to win the war as time progressed, and in mid-1944 he decided to switch sides. Upon their capture of Rangoon in 1942, the Japanese established a puppet state, the State of Burma, and reorganised the BIA as its armed forces, the Burma National Army (BNA).

This group came to be known as the Thirty Comrades, and upon returning to Burma in 1941 they established the Burma Independence Army (BIA) to fight against the Allies. In 1940, during World War II, a group of young Burmese intellectuals left for Japan to receive military training in preparation for an anti-colonial struggle against the British.
