During World War II , Imperial Japan invaded most of the former western colonies . The Shōwa occupation regime committed violent actions against civilians such as the Manila massacre and the implementation of a system of forced labour , such as the one involving 4 to 10 million '' romusha '' in Indonesia . A later UN report stated that four million people died in Indonesia as a result of famine and forced labour during the Japanese occupation . The Allied powers who defeated Japan in the South-East Asian theatre of World War II then contended with nationalists to whom the occupation authorities had granted independence
Manila massacre
Manila massacre
Southeast Asia