Greater Thailand and Indochina, 1945

After the fall of France, Japan occupied Indochina with the reluctant cooperation of Vichy France, while awarding parts of it to Thailand (which briefly invaded the colony). Thailand later annexed parts of British Burma and Malaya as well after Japan conquered those regions from the British. Late in the war, after the fall of Vichy France, Japan overthrew the French administration in Indochina to stop them from defecting to the Free French and established three independent states. The Kingdom of Luang Prabang, a kingdom inside the French protectorate of Laos, was expanded to include all of Laos, while the Kingdom of Cambodia became independent as the Kingdom of Kampuchea. Tonkin, Annam, and Cochinchina were merged to form the Empire of Vietnam, under the Nguyen Dynasty (which already ruled Annam and, nominally, Tonkin). Cochinchina, formerly under direct French rule, remained under direct Japanese administration for the time being, but it was agreed that it would become part of Vietnam.

I used the pre-war subdivisions for the Indochinese kingdoms; as far as I'm aware, no new administrative system was established inside the former protectorates. I think Thailand's borders and subdivisions are reasonably accurate.