 The Japanese regime perceived Java as the most politically sophisticated but economically the least important area; its people were Japan's main resource.As such—and in contrast to Dutch suppression—the Japanese encouraged Indonesian nationalism in Java and thus increased its political sophistication (similar encouragement of nationalism in strategic resource-rich Sumatra came later, but only after it was clear the Japanese would lose the war).The outer islands under naval control, however, were regarded as politically backward but economically vital for the Japanese war effort, and these regions were governed the most oppressively of all.