 Beginning in the 1930s , Imperial Japan attempted to expand its territory into China . Opposed to these aggressive actions , the United States , Britain , and the Netherlands froze Japanese assets and imposed economic restrictions which prohibited the exportation of aircraft fuel as well as steel and iron to Japan , affecting 90 % of Japan 's war production needs . Japan was forced to either give up its expansion plans or find alternative raw materials to continue producing equipment for the war . Japan chose to continue with its plans , but decided it needed to neutralize any threat from the United States first . 
