Imperial Japanese Navy ship classifications

Imperial Japanese Navy ship classifications went through various changes between 1871 and 1945, as technology changed and new ship classes were added while those that became obsolete were discontinued. There were efforts to translate some ships' classes that were imported or in use by other navies, while incorporating any classification system into Japanese language conventions and maintaining an internal consistency.

Classification terminology
These were legal classifications of the naval vessels of the Imperial Japanese Navy. Therefore, those names are different from universal classifications and class names.

In laws, ordinances, regulations, and policies pertaining to the Imperial Japanese Navy, there were no classifications related to the light aircraft carrier, escort carrier, heavy cruiser or light cruiser. Even if it is assumed that these translation were different in the Japanese language, there could be the same phrase and class in English language, and vice versa.
 * Example 1: Kōsakukan (工作艦) and Kōsakusen (工作船) = Repair ship.
 * Example 2: Fusetukan (敷設艦), Fusetsusen (敷設船), and Fusetsutei (敷設艇) = Minelayer.

The suffix of ship classes could also relate the type or structure of the vessel, which may carry a slightly different connotation than the translated English term. SOme examples:
 * -kan (艦) = Vessel or Ship, example: Kōsakukan is Repair vessel; Senkan is a Battleship.
 * -sen (船) = Ship, example: Kōsakusen is Repair ship.
 * -tei (艇) = Boat, example: Fusetsutei is Mine boat.

28 October 1871 (Initial)

 * 28 October 1871, Rules of the Navy, and officer's salary schedules, Article 3 and 4, Ministry of War (明治4年10月28日 兵部省 海軍規則並諸官俸給表 第3條および第4條, 1871 Kaigun kisoku narabini shokan hōkyūhyō)

5 October 1872

 * 5 October 1872, Revision of the Naval ship classes (明治5年10月4日 海軍省軍務局 艦船等級更正ノ件, 1872 Kansen tōkyū kōsei-no ken)

13 August 1890

 * 13 August 1890, Notice No. 291, "Naval ships ordinance, Article 2", Minister's Secretariat (明治23年8月13日 海軍大臣官房 達第291号 海軍艦船籍條例 第2條, 1890 Kaigun kansenseki jōrei)

1 April 1896

 * 1896 Imperial edict No. 71, "Naval ships ordinance, Article 3" (明治29年 勅令第71号 海軍艦船條例 第3條, 1896 Chokurei Dai-71-gō, Kaigun kansen jōrei)

21 March 1898

 * Standard classifications of the naval warships and torpedo boats (海軍軍艦及水雷艇類別標準, Kaigun gunkan oyobi suiraitei ruibetsu-hyōjun)

22 June 1900

 * Standard classifications of the naval vessels (海軍艦艇類別標準, Kaigun kantei ruibetsu-hyōjun)

28 August 1912

 * Standard classifications of the naval vessels

17 May 1916

 * Standard classifications of the naval vessels

1 April 1920

 * Standard classifications of the naval vessels


 * Standard classifications of the naval auxiliary vessels (海軍特務艦艇類別標準, Kaigun tokumu-kantei ruibetsu-hyōjun)

1 December 1924

 * Standard classifications of the naval vessels


 * Standard classifications of the naval auxiliary vessels

2 March 1927

 * Standard classifications of the naval vessels


 * Standard classifications of the naval auxiliary vessels

30 May 1931

 * Standard classifications of the naval vessels


 * Standard classifications of the naval auxiliary vessels

26 June 1941

 * Standard classifications of the naval vessels


 * Standard classifications of the naval auxiliary vessels

30 June 1945 (Final)

 * Standard classifications of the naval vessels


 * Standard classifications of the naval auxiliary vessels

Cruiser




Minelaying ship/Minelayer/Rapid extension netlayer

 * Note; pertinence of rapid extension netlayer was only JAPANESE MINELAYER Shirataka.

Training battleship

 * Note; pertinence of training battleship was only JAPANESE BATTLESHIP Hiei. She does not return to battleship in the Imperial Japanese Navy's official documents.

Training cruiser

 * Note; pertinence of training cruiser was only Katori-class cruiser.

Submersible/Submarine

 * Note; Kō-hyōteki, Kairyū and Kaiten were not included in this table, because they were weapons in the Imperial Japanese Navy's official documents.

Mine boat/Capture-net layer

 * Note; pertinence of capture net layer was only Tsubame-class minelayer.

Cable layer

 * Note; pertinence of cable layer was only Hashima-class cable layer.

Landing ship

 * Note 1; pertinence of 1st class landing ship was only No.1-class landing ship.
 * Note 2; pertinence of 2nd class lamding ship was only No.101-class landing ship.

Coast defence boat

 * Note; there is not a ship classed on this table. All No.1-class coast defence boat and No.101-class coast defence boat vessels were incomplete.

Transport vessel/Transport ship



 * Note; Included replenishment oiler (給油船/給油艦, Kyūyusen/Kyūyukan), collier (給炭船/給炭艦, Kyūtansen/Kyūtankan), collier-oiler (給炭油艦, Kyūtan'yukan), munition ship (給兵艦, Kyūheikan), food supply ship (給糧艦, Kyūryōkan) and freighter (雑用艦, Zatsuyōkan).

Hospital ship

 * Note; there is not a ship classed on this table.

Icebreaker

 * Note; pertinence of icebreaker was only JAPANESE ICEBREAKER Ōtomari.

Target ship

 * This section treats a self-propelled target ship. Towed target ship is miscellaneous ship.

17 September 1903 (Initial)

 * 17 September 1903, Notice No. 90, Quorum and kinds of miscellaneous ship in naval units, Minister's Secretariat, Ministry of the Navy (明治36年9月17日 海軍大臣官房 達第90号 海軍各廳附属雑役船ノ種類及定数, 1903 Tatsu Dai-90-Gō, Kaigun kakuchō fuzoku zatsuekisen-no shurui oyobi teisū)

23 December 1916 (Initial)

 * 23 December 1916, Ministerial ordinance No. 281, Special service ships and units ordinance, Minister's Secretariat, Ministry of the Navy (大正5年12月23日 海軍大臣官房 内令第281号 特設艦船部隊令, 1916 Nairei Dai-281-Gō, Tokusetsukansen butairei)

February 1945 (Final)

 * February 1945, Ministerial ordinance No. 83, Special service ships and units ordinance, Minister's Secretariat, Ministry of the Navy (昭和20年2月 海軍大臣官房 内令第83号, 1945 Nairei Dai-83-Gō)