Kansen (Naval Vessels)
Shubetsu (Category)
Ruibetsu (Class)
Tokyu (Grade)
Kantei (Vessels and Boats)
Gunkan (Warships)
Senkan (Battleships)
Junyokan (Cruisers)
Itto-Junyokan (1st Class Cruisers)
Nito-Junyokan (2nd Class Cruisers)
Koku-bokan (Aircraft Carriers)
Suijoki-bokan (Seaplane Tenders)
Sensui-bokan (Submarine Tenders)
Fusetsukan (Minelayers)
Renshu-senkan (Training Buttleships)
Renshu-junyokan (Training Cruisers)
Kuchikukan (Destroyers)
Kuchikukan (Destroyers)
Itto-Kuchikukan (1st Class Destroyers)
Nito-Kuchikukan (2nd Class Destroyers)
Sensuikan (Submarines)
Sensuikan (Submarines)
Itto-Sensuikan (1st Class Submarines)
Nito-Sensuikan (2nd Class Submarines)
Hokan (Gunboats)
Hokan (Gunboats)
Kaibokan (Frigates)
Kaibokan (Frigates)
Yusokan (Transports/Landing Ships)
Yusokan (Transports/Landing Ships)
Itto-Yusokan (High Speed Transports)
Nito-Yusokan (Landing Ships)
Suiraitei (Torpedo Boats)
Suiraitei (Torpedo Boats)
Sokaitei (Minesweepers)
Sokaitei (Minesweepers)
Kusentei (Subchasers)
Kusentei (Subchasers)
Fusetsutei (Small Minelayers)
Fusetsutei (Small Minelayers)
Shokaitei (Patrol Boats)
Shokaitei (Patrol Boats)
Tokumukantei (Auxiliaries)
Tokumukan (Auxiliary Vessels)
Kosakukan (Repair Ships)
Unsokan (Transports/Cargo Ships/Fleet Replenishment Ships)
Saihyokan (Icebreakers)
Sokuryokan (Survey Vessels)
Hyotekikan (Target Ships)
Renshu-tokumukan (Training Auxiliaries)
Tokumutei (Auxiliary Boats)
Fusetsu-tokumutei (Auxiliary Minelayers)
Shokai-tokumutei (Auxiliary Patrolboats)
Kusen-tokumutei (Auxiliary Subchasers)
Sokai-tokumutei (Auxiliary Minesweepers)
Kaibotei (Suicide-Torpedo Carriers)
Sensuikan-botei (Auxiliary Submarine Tenders)
Denran-fusetsutei (Controlled Mine Layers)
Gyoraitei (Motor Torpedo Boats)
(Zatsuekisen）
Zatsuekisen (Miscellaneous Harbour Ships)
Tokusetsukansen (Temporary Naval Vessels)
＊＊＊＊＊
IJN categorized its vessels on the basis of "Shubetsu" (category) which was set forth in "Kansenrei" (Order for the naval vessels).
Further IJN set up more detail standard of "Ruibetsu" (class) and "Tokyu" (grade) in Shubetsu. These order and standard were revised several times.
Hokan or Kaibokan was one of Gunkan at early stage. IJN set forth new category of Kaibokan on 1 July 1942 and Hokan on 1 October 1944 respectively.
Fusetsutei was one of Tokumutei. On 1 February 1944 IJN set forth new Ruibetsu of Fusetsu-tokumutei in Tokumutei while it set forth new Shubetsu of Fusetsutei in Kantei.
Shokaitei was also one of Tokumutei. IJN set forth new Shubetsu of Shokaitei in Kantei on 15 February 1943.
The above table shows category, class, and grade at the end of war.
IJN usually used Shubetsu. For example IJN called Battleship YAMATO "Gunkan Yamato", not "Senkan Yamato".