It was the primary fighter used by Japan during the war. It was the primary enemy of US Naval aircraft such as the Grumman F4F Wildcat, Vought F4U Corsair, and later the Grumman F6F Hellcat, which was specifically designed to combat the Zero. The A6M Zero was the best fighter at the beginning of the Pacific war. However, late in the war, new American fighters were able to defeat it.