The Battle of Midway is widely regarded as the most important naval battle of the Pacific Campaign of World War II. Between 4 and 7 June 1942, approximately one month after the Battle of the Coral Sea and six months after Japan's attack on Pearl Harbor, the United States Navy decisively defeated an Imperial Japanese Navy (IJN) attack against Midway Atoll, inflicting irreparable damage on the Japanese.
The Japanese operation, like the earlier attack on Pearl Harbor, aimed to eliminate the United States as a strategic power in the Pacific, thereby giving Japan a free hand in establishing its Greater East Asia Co-Prosperity Sphere. The Japanese hoped that another demoralizing defeat would force the U.S. to capitulate in the Pacific War.
The Japanese plan was to lure the United States' few remaining aircraft carriers into a trap. The Japanese also intended to occupy Midway Atoll as part of an overall plan to extend their defensive perimeter in response to the Doolittle Raid. This operation was considered preparatory for further attacks against Fiji and Samoa.
The plan was handicapped by faulty Japanese assumptions of American reaction and poor initial dispositions. Most significantly, American codebreakers were able to determine the date and location of the attack, enabling the forewarned U.S. Navy to set up an ambush of its own. Four Japanese aircraft carriers and a heavy cruiser were sunk in exchange for one American aircraft carrier and a destroyer. The heavy losses in carriers and aircrews permanently weakened the Imperial Japanese Navy. Japan's shipbuilding and pilot training programs were unable to keep pace in replacing their losses, while the U.S. steadily increased output in both areas.