* View and specifications as reconstructed at 1935-38. Aircraft as in the largest known Air Group ever carried (during the Pearl Harbor raid).

Akagi was laid down on 6 December 1920 at Kure Naval Dockyard as one of four Amagi class battlecruisers. However, the Wa­shi­n­gton Naval Treaty, signed in 1922, prevented Japan from completing these ships. The incomplete hulls of Akagi and her sistership Amagi were selected for completion as aircraft carriers, but Amagi's hull was damaged beyond repair in an ear­th­quake. Akagi, the only remaining member of her class, was launched on 22 April 1925 and completed on 27 March 1927.

As completed, the ship had two hangar decks, the hangars opened onto two superimposed flying off decks at the bow. In theory, this per­mitted aircraft to take off directly from the hangars, while landing on the main flight deck above. In practice, the multiple flight deck ar­ran­ge­ment proved unsuccessful. From 1935 to 1938, Akagi received a massive reconstruction at Sasebo Naval Arsenal. It extended the hangars forward, removed the flying off decks, increased aircraft capacity, and added an island superstructure on the unusual port side of the ship.

Akagi was active off China during the next few years as the flagship of Carrier Division 1. As the flagship of the First Air Fleet (combined the First, Second,  and Fifth Carrier Divisions in April 1941) Akagi took part in the attack on Pearl Harbor and Darwin, the invasion of Rabaul and Java, the Indian Ocean raids, and the battle of Midway, where she was hit by two (probably only one) bombs at 1025, 4 June 1942. The hits caused massive fires and secondary explosions among fueled and armed aircraft on the hangar decks and jammed the rudder. Four and a half hours after the attack the crew was ordered to abandon Akagi. The doomed ship was scuttled by torpedoes from her escort destroyers at 0520, 5 June 1942, at position 30°30' N 178°40' W.