Political map of East Asia and the Western Pacific 23 January 1942 (Japanese Onslaught in the Pacific): Following Pearl Harbor, the Japanese quickly overran Allied possessions in China, Southeast Asia, and the Pacific (Pacific War) as they moved to seize resources and secure a strategic island perimeter (Greater East Asia Co-Prosperity Sphere). The Americans, British, Dutch and Australians responded by forming a joint command (ABDA) (American-British-Dutch-Australian Command) in an attempt to coordinate a defense.