Japanese Navy Organization
Early War Organization (from smallest to largest)
Carrier Divisions - Koku Sentais - These were the smallest groups of the Japanese Navy. The Koku Sentais consisted of two aircraft carriers and a varying number of Koku Sentais.
Area Fleets - Homen Kantais
Air Fleets - Koku Kantais
Fleets - Kantais
Navy Air Headquarters - Kaigun Koku Hombu - Responsible for aircraft, engines and equipment of the Navy, as well as testing of said equipment. They were also in charge of training of flight and maintenance personnel.
Chief of Navy General Staff - Gunreibu Socho
Imperial General Headquarters - Daihonei
Late War Reorganization
Reorganization was caused late in the war by the necessity of adding land based planes to their arsenal, mainly because they had so few carriers left.
Naval Air Corps - Kokutais
Koku Kanais consisted of