Akagi was an aircraft carrier of the Imperial Japanese Navy, originally begun as an Amagi-class battlecruiser. She was converted under the terms of the Washington Naval Treaty to an aircraft carrier. The ship was rebuilt from 1935 to 1938 with her original three flight decks consolidated into a single enlarged flight deck, a greater capacity for aircraft and she also received an island superstructure.
Akagi's aircraft participated in the Second Sino-Japanese War in the late 1930s. She took part in the Pearl Harbor raid in December 1941 and the invasion of Rabaul in the Southwest Pacific in January 1942. The following month her aircraft bombed Darwin, Australia. The ship took part in the Indian Ocean raid and was damaged severely enough during the Battle of Midway on 4 June 1942 that she was scuttled by Japanese destroyers to prevent her from falling into enemy hands. The loss of Akagi and three other IJN carriers at Midway was a crucial strategic defeat for Japan and contributed significantly to Japan's ultimate defeat in the war.