After the attack on Pearl Harbor on December 7, 1941, the Japanese Navy and its Air force were defeated in several important battles, like Midway and the Philippine Sea. They lost many ships (including nearly all the Japanese aircraft carriers), hundreds of fighter aircraft, and many of their best pilots. The Japanese industry was small and very poor compared to the American industry. For this reason, the United States replaced their lost ships and planes with better ones very quickly; but Japan could only make few, and of poor quality. During 1943-44, the Allied forces were moving towards Japan. At the Battle of the Philippine Sea, on June 19-20, 1944, the Japanese forces were pushed back to the Philippines.