Mindful of the huge wartime industrial potential of America, yet hopeful that Axis successes in Europe would limit what the Allies could undertake in the Pacific, the Imperial Japanese Navy (IJN) pursued their time-honored strategy of winning a decisive battle at the beginning of a short war, after which she could dictate peace terms. On December 7, 1941, Japan boldly launched a series of nearly simultaneous land and sea assaults. One of these temporarily crippled the American navy by destroying its battleship fleet at Pearl Harbor. Over the next four months, Japan's army and navy drove the Americans out of the Philippines and neutralized potential American stepping stones back to the Philippines by overrunning Wake Island and Guam. Against the British, Japan sank prized battleships, invaded possessions in Malaya and Borneo, forced the surrender of Singapore, and neutralized the British position in Ceylon. Dutch possessions in the East Indies were also overrun, giving Japan access to vast quantities of oil. Australia was driven out of New Britain and parts of New Guinea. Japan then established a defensive perimeter around her expanded empire by fortifying bases at many of the newly conquered possessions.