Once the Pacific War began, the Imperial Japanese Army quickly captured many critical areas. These included British Malaya, Guam, the Philippines and Wake Island. A combination of Japanese naval supremacy and the Allied doctrine of 'Europe first' meant they saw relatively little opposition during this stage of the war – 85% of American resources, and 68% of Army personnel went towards the European Theater. The Japanese control of a large part of Oceania and Asia gave them a strong initiative, as they were able to acquire many valuable resources, including rubber, tin, bauxite and oil – Japan had no domestic sources of oil, but in 1942 the Dutch East Indies was the fourth largest global producer of oil.