- originally planned as an Amagi-class battlecruiser in the '20s, she was converted into an aircraft carrier with 3 flight decks to conform with the Washington Naval Treaty. Reconstructed 1935-1938, the 2 lower flight decks converted into hangars, with the top flight deck lengthened.
- She was the flag ship of the 1st Air Fleet - Kidou Butai; from the Attack on Pearl Harbor in 1941, until her scuttling after the Battle of Midway mid-1942
https://en.wikipedia.org/wiki/Japanese_aircraft_carrier_Akagi