Imperial Japanese Navy ship classifications
# 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.

## Representative classification tables

### 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)

| Warship (軍艦, Gunkan) | Large vessel (大艦, Daikan) | 1st class warship (一等軍艦, Ittō Gunkan) | Ironclad warship: And over 450 horsepower steamship Others: And over 600 horsepower steamship, or, and over 500 crewmen |
| - | - | - | - |
| Warship (軍艦, Gunkan) | Large vessel (大艦, Daikan) | 2nd class warship (二等軍艦, Nitō Gunkan) | Ironclad warship: And over 150 hp steamship Others: And over 450 hp steamship, or, and over 300 crewmen |
| Warship (軍艦, Gunkan) | Medium vessel (中艦, Chūkan) | 3rd class warship (三等軍艦, Santō Gunkan) | Ironclad warship: Less than 150 hp steamship Others: And over 250 hp steamship, or, and over 200 crewmen |
| Warship (軍艦, Gunkan) | Medium vessel (中艦, Chūkan) | 4th class warship (四等軍艦, Yontō Gunkan) | And over 150 hp steamship, or, and over 120 crewmen |
| Warship (軍艦, Gunkan) | Small vessel (小艦, Shōkan) | 5th class warship (五等軍艦, Gotō Gunkan) | And over 80 hp steamship, or, and over 50 crewmen |
| Warship (軍艦, Gunkan) | Small vessel (小艦, Shōkan) | 6th class warship (六等軍艦, Rokutō Gunkan) | And over 50 hp steamship, or, and over 30 crewmen |
| Warship (軍艦, Gunkan) | Small vessel (小艦, Shōkan) | 7th class warship (七等軍艦, Nanatō Gunkan) | Less than 50 hp steamship, or, and less than 30 crewmen |

### 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)

| Warship | Large vessel | 1st class warship | Ironclad warship: And over 170 crewmen Others: And over 455 crewmen |
| - | - | - | - |
| Warship | Large vessel | 2nd class warship | Ironclad warship: And over 65 crewmen Others: And over 315 crewmen |
| Warship | Large vessel | 3rd class warship | Ironclad warship: Less than 65 crewmen Others: And over 170 crewmen |
| Warship | Medium vessel | 4th class warship | And over 100 crewmen |
| Warship | Medium vessel | 5th class warship | And over 65 crewmen |
| Warship | Small vessel | 6th class warship | And over 40 crewmen |
| Warship | Small vessel | 7th class warship | Less than 39 crewmen |
| Transport vessel (運送艦, Unsōkan) | Transport vessel (運送艦, Unsōkan) | 4th class transport vessel (四等運送艦, Yontō Unsōkan) | And over 800 tons displacement |
| Transport vessel (運送艦, Unsōkan) | Transport vessel (運送艦, Unsōkan) | 5th class transport vessel (五等運送艦, Gotō Unsōkan) | And over 500 tons displacement |
| Transport vessel (運送艦, Unsōkan) | Transport vessel (運送艦, Unsōkan) | 6th class transport vessel (六等運送艦, Rokutō Unsōkan) | And over 200 tons displacement |
| Transport vessel (運送艦, Unsōkan) | Transport vessel (運送艦, Unsōkan) | 7th class transport vessel (七等運送艦, Nanatō Unsōkan) | And under 200 tons displacement |

### 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)

| Naval ships (海軍艦船, Kaigun Kansen) | Category 'A' ship (第一種艦船, Daiisshu Kansen) | Warship as fighting ship (戦闘航海ノ役務ニ堪フル軍艦, Sentōkōkai-no ekimu-ni tauru gunkan) |
| - | - | - |
| Naval ships (海軍艦船, Kaigun Kansen) | Category 'B' ship (第二種艦船, Dainishu Kansen) | Torpedo boat (水雷艇, Suiraitei) |
| Naval ships (海軍艦船, Kaigun Kansen) | Category 'C' ship (第三種艦船, Daisanshu Kansen) | Warship as noncombatant ship (戦闘航海ノ役務ニ堪ヘサル軍艦, Sentōkōkai-no ekimu-ni taezaru gunkan) |
| Naval ships (海軍艦船, Kaigun Kansen) | Category 'D' ship (第四種艦船, Daiyonshu Kansen) | Transport ship (運送船, Unsōsen), Tugboat (曳船, Eisen) and Small sized steamer (小蒸気船, Shō jōkisen) |
| Naval ships (海軍艦船, Kaigun Kansen) | Category 'E' ship (第五種艦船, Daigoshu Kansen) | Storage ship (倉庫船, Sōkosen), Loading ship (荷船, Nisen) and Miscellaneous ship (雑船, Zatsusen) |

### 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)

| Naval ships | Category 'A' warship (第一種軍艦, Daiisshu Gunkan) | Warship as fighting ship |
| - | - | - |
| Naval ships | Category 'B' warship (第二種軍艦, Dainishu Gunkan) | Warship as noncombatant ship |
| Naval ships | Torpedo boat | 1st class torpedo boat (一等水雷艇, Ittō Suiraitei) |
| Naval ships | Torpedo boat | 2nd class torpedo boat (二等水雷艇, Nitō Suiraitei) |
| Naval ships | Torpedo boat | 3rd class torpedo boat (三等水雷艇, Santō Suiraitei) |
| Naval ships | Miscellaneous ships (雑役船舟, Zatsuekisenshū) | |

### 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)

| Warships | Battleship (戦艦, Senkan) | 1st class battleship (一等戦艦, Ittō Senkan) |
| - | - | - |
| Warships | Battleship (戦艦, Senkan) | 2nd class battleship (二等戦艦, Nitō Senkan) |
| Warships | Cruiser (巡洋艦, Jun'yōkan) | 1st class cruiser (一等巡洋艦, Ittō Jun'yōkan) |
| Warships | Cruiser (巡洋艦, Jun'yōkan) | 2nd class cruiser (二等巡洋艦, Nitō Jun'yōkan) |
| Warships | Cruiser (巡洋艦, Jun'yōkan) | 3rd class cruiser (三等巡洋艦, Santō Jun'yōkan) |
| Warships | Coast defence ship (海防艦, Kaibōkan) | 1st class coast defence ship (一等海防艦, Ittō Kaibōkan) |
| Warships | Coast defence ship (海防艦, Kaibōkan) | 2nd class coast defence ship (二等海防艦, Nitō Kaibōkan) |
| Warships | Coast defence ship (海防艦, Kaibōkan) | 3rd class coast defence ship (三等海防艦, Santō Kaibōkan) |
| Warships | Gunboat (砲艦, Hōkan) | 1st class gunboat (一等砲艦, Ittō Hōkan) |
| Warships | Gunboat (砲艦, Hōkan) | 2nd class gunboat (二等砲艦, Nitō Hōkan) |
| Warships | Dispatch vessel (通報艦, Tsūhōkan) | |
| Warships | Torpedo boat tender (水雷母艦, Suiraibokan) | |
| Torpedo boat | Torpedo boat | Torpedo boat destroyer (水雷艇駆逐艇, Suiraiteikuchikutei) |
| Torpedo boat | Torpedo boat | 1st class torpedo boat |
| Torpedo boat | Torpedo boat | 2nd class torpedo boat |
| Torpedo boat | Torpedo boat | 3rd class torpedo boat |
| Torpedo boat | Torpedo boat | 4th class torpedo boat (四等水雷艇, Yontō Suiraitei) |

### 22 June 1900

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

| Naval vessels (艦艇, Kantei) | Warships | Battleship | 1st class battleship |
| - | - | - | - |
| Naval vessels (艦艇, Kantei) | Warships | Battleship | 2nd class battleship |
| Naval vessels (艦艇, Kantei) | Warships | Cruiser | 1st class cruiser |
| Naval vessels (艦艇, Kantei) | Warships | Cruiser | 2nd class cruiser |
| Naval vessels (艦艇, Kantei) | Warships | Cruiser | 3rd class cruiser |
| Naval vessels (艦艇, Kantei) | Warships | Coast defence ship | 1st class coast defence ship |
| Naval vessels (艦艇, Kantei) | Warships | Coast defence ship | 2nd class coast defence ship |
| Naval vessels (艦艇, Kantei) | Warships | Coast defence ship | 3rd class coast defence ship |
| Naval vessels (艦艇, Kantei) | Warships | Gunboat | 1st class gunboat |
| Naval vessels (艦艇, Kantei) | Warships | Gunboat | 2nd class gunboat |
| Naval vessels (艦艇, Kantei) | Warships | Dispatch vessel | |
| Naval vessels (艦艇, Kantei) | Warships | Torpedo boat tender | |
| Naval vessels (艦艇, Kantei) | Warships | Destroyer (駆逐艦, Kuchikukan) | |
| Naval vessels (艦艇, Kantei) | Torpedo boat | Torpedo boat | 1st class torpedo boat |
| Naval vessels (艦艇, Kantei) | Torpedo boat | Torpedo boat | 2nd class torpedo boat |
| Naval vessels (艦艇, Kantei) | Torpedo boat | Torpedo boat | 3rd class torpedo boat |
| Naval vessels (艦艇, Kantei) | Torpedo boat | Torpedo boat | 4th class torpedo boat |

### 28 August 1912

* Standard classifications of the naval vessels

| Naval vessels | Warships | Battleship | |
| - | - | - | - |
| Naval vessels | Warships | Battlecruiser (巡洋戦艦, Jun'yōsenkan) | |
| Naval vessels | Warships | Cruiser | 1st class cruiser |
| Naval vessels | Warships | Cruiser | 2nd class cruiser |
| Naval vessels | Warships | Coast defence ship | 1st class coast defence ship |
| Naval vessels | Warships | Coast defence ship | 2nd class coast defence ship |
| Naval vessels | Warships | Gunboat | 1st class gunboat |
| Naval vessels | Warships | Gunboat | 2nd class gunboat |
| Naval vessels | Destroyer | Destroyer | |
| Naval vessels | Torpedo boat | Torpedo boat | 1st class torpedo boat |
| Naval vessels | Torpedo boat | Torpedo boat | 2nd class torpedo boat |
| Naval vessels | Submersible (潜水艇, Sensuitei) | Submersible (潜水艇, Sensuitei) | |
| Repair ship (工作船, Kōsakusen) | Repair ship (工作船, Kōsakusen) | Repair ship (工作船, Kōsakusen) | |
| Transport ship | Transport ship | Transport ship | |
| Hospital ship (病院船, Byōinsen) | Hospital ship (病院船, Byōinsen) | Hospital ship (病院船, Byōinsen) | |

### 17 May 1916

* Standard classifications of the naval vessels

| Naval vessels | Warships | Battleship | |
| - | - | - | - |
| Naval vessels | Warships | Battlecruiser | |
| Naval vessels | Warships | Cruiser | 1st class cruiser |
| Naval vessels | Warships | Cruiser | 2nd class cruiser |
| Naval vessels | Warships | Coast defence ship | 1st class coast defence ship |
| Naval vessels | Warships | Coast defence ship | 2nd class coast defence ship |
| Naval vessels | Warships | Gunboat | 1st class gunboat |
| Naval vessels | Warships | Gunboat | 2nd class gunboat |
| Naval vessels | Destroyer | Destroyer | 1st class destroyer (一等駆逐艦, Ittō Kuchikukan) |
| Naval vessels | Destroyer | Destroyer | 2nd class destroyer (二等駆逐艦, Nitō Kuchikukan) |
| Naval vessels | Destroyer | Destroyer | 3rd class destroyer (三等駆逐艦, Santō Kuchikukan) |
| Naval vessels | Torpedo boat | Torpedo boat | 1st class torpedo boat |
| Naval vessels | Torpedo boat | Torpedo boat | 2nd class torpedo boat |
| Naval vessels | Submersible | Submersible | |
| Auxiliary ships (特務船, Tokumusen) | Repair ship | Repair ship | |
| Auxiliary ships (特務船, Tokumusen) | Transport ship | Transport ship | |
| Auxiliary ships (特務船, Tokumusen) | Minelaying ship (敷設船, Fusetsusen) | Minelaying ship (敷設船, Fusetsusen) | |

### 1 April 1920

* Standard classifications of the naval vessels

| Naval vessels | Warships | Battleship | |
| - | - | - | - |
| Naval vessels | Warships | Battlecruiser | |
| Naval vessels | Warships | Cruiser | 1st class cruiser |
| Naval vessels | Warships | Cruiser | 2nd class cruiser |
| Naval vessels | Warships | Aircraft carrier (航空母艦, Kōkūbokan) | |
| Naval vessels | Warships | Torpedo boat tender | |
| Naval vessels | Warships | Minelayer (敷設艦, Fusetsukan) | |
| Naval vessels | Warships | Coast defence ship | 1st class coast defence ship |
| Naval vessels | Warships | Coast defence ship | 2nd class coast defence ship |
| Naval vessels | Warships | Gunboat | 1st class gunboat |
| Naval vessels | Warships | Gunboat | 2nd class gunboat |
| Naval vessels | Destroyer | Destroyer | 1st class destroyer |
| Naval vessels | Destroyer | Destroyer | 2nd class destroyer |
| Naval vessels | Destroyer | Destroyer | 3rd class destroyer |
| Naval vessels | Torpedo boat | Torpedo boat | 1st class torpedo boat |
| Naval vessels | Torpedo boat | Torpedo boat | 2nd class torpedo boat |
| Naval vessels | Submarine (潜水艦, Sensuikan) | Submarine (潜水艦, Sensuikan) | 1st class submarine (一等潜水艦, Ittō Sensuikan) |
| Naval vessels | Submarine (潜水艦, Sensuikan) | Submarine (潜水艦, Sensuikan) | 2nd class submarine (二等潜水艦, Nitō Sensuikan) |
| Naval vessels | Submarine (潜水艦, Sensuikan) | Submarine (潜水艦, Sensuikan) | 3rd class submarine (三等潜水艦, Santō Sensuikan) |

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

| Auxiliary vessels (特務艦艇, Tokumu-kantei) | Auxiliary vessel (特務艦, Tokumukan) | Repair vessel (工作艦, Kōsakukan) | |
| - | - | - | - |
| Auxiliary vessels (特務艦艇, Tokumu-kantei) | Auxiliary vessel (特務艦, Tokumukan) | Transport vessel | |
| Auxiliary vessels (特務艦艇, Tokumu-kantei) | Auxiliary boat (特務艇, Tokumutei) | Minesweeper (掃海艇, Sōkaitei) | 1st class minesweeper (一等掃海艇, Ittō Sōkaitei) |
| Auxiliary vessels (特務艦艇, Tokumu-kantei) | Auxiliary boat (特務艇, Tokumutei) | Minesweeper (掃海艇, Sōkaitei) | 2nd class minesweeper (二等掃海艇, Nitō Sōkaitei) |
| Auxiliary vessels (特務艦艇, Tokumu-kantei) | Auxiliary boat (特務艇, Tokumutei) | Submarine depot boat (潜水艦母艇, Sensuikanbotei) | |

### 1 December 1924

* Standard classifications of the naval vessels

| Naval vessels | Warships | Battleship | |
| - | - | - | - |
| Naval vessels | Warships | Battlecruiser | |
| Naval vessels | Warships | Cruiser | 1st class cruiser |
| Naval vessels | Warships | Cruiser | 2nd class cruiser |
| Naval vessels | Warships | Aircraft carrier | |
| Naval vessels | Warships | Submarine tender (潜水母艦, Sensuibokan) | |
| Naval vessels | Warships | Minelayer | |
| Naval vessels | Warships | Coast defence ship | 1st class coast defence ship |
| Naval vessels | Warships | Coast defence ship | 2nd class coast defence ship |
| Naval vessels | Warships | Gunboat | 1st class gunboat |
| Naval vessels | Warships | Gunboat | 2nd class gunboat |
| Naval vessels | Destroyer | Destroyer | 1st class destroyer |
| Naval vessels | Destroyer | Destroyer | 2nd class destroyer |
| Naval vessels | Destroyer | Destroyer | 3rd class destroyer |
| Naval vessels | Submarine | Submarine | 1st class submarine |
| Naval vessels | Submarine | Submarine | 2nd class submarine |
| Naval vessels | Submarine | Submarine | 3rd class submarine |
| Naval vessels | Minesweeper | Minesweeper | |

* Standard classifications of the naval auxiliary vessels

| Auxiliary vessels | Auxiliary vessel | Repair vessel | |
| - | - | - | - |
| Auxiliary vessels | Auxiliary vessel | Transport vessel | |
| Auxiliary vessels | Auxiliary vessel | Icebreaker (砕氷艦, Saihyōkan) | |
| Auxiliary vessels | Auxiliary vessel | Survey ship (測量艦, Sokuryōkan) | |
| Auxiliary vessels | Auxiliary vessel | Target ship (標的艦, Hyōtekikan) | |
| Auxiliary vessels | Auxiliary vessel | Auxiliary training ship (練習特務艦, Renshūtokumukan) | |
| Auxiliary vessels | Auxiliary boat | Mine boat (敷設艇, Fusetsutei) | 1st class mine boat (一等敷設艇, Ittō Fusetsutei) |
| Auxiliary vessels | Auxiliary boat | Mine boat (敷設艇, Fusetsutei) | 2nd class mine boat (二等敷設艇, Nitō Fusetsutei) |
| Auxiliary vessels | Auxiliary boat | Mine boat (敷設艇, Fusetsutei) | 3rd class mine boat (三等敷設艇, Santō Fusetsutei) |
| Auxiliary vessels | Auxiliary boat | Auxiliary minesweeper (掃海特務艇, Sōkaitokumutei) | 1st class auxiliary minesweeper (一等掃海特務艇, Ittō Sōkaitokumutei) |
| Auxiliary vessels | Auxiliary boat | Auxiliary minesweeper (掃海特務艇, Sōkaitokumutei) | 2nd class auxiliary minesweeper (二等掃海特務艇, Nitō Sōkaitokumutei) |
| Auxiliary vessels | Auxiliary boat | Submarine depot boat | |

### 2 March 1927

* Standard classifications of the naval vessels

| Naval vessels | Warships | Battleship | |
| - | - | - | - |
| Naval vessels | Warships | Battlecruiser | |
| Naval vessels | Warships | Cruiser | 1st class cruiser |
| Naval vessels | Warships | Cruiser | 2nd class cruiser |
| Naval vessels | Warships | Aircraft carrier | |
| Naval vessels | Warships | Submarine tender | |
| Naval vessels | Warships | Minelayer | |
| Naval vessels | Warships | Rapid extension netlayer (急設網艦, Kyūsetsumōkan) | |
| Naval vessels | Warships | Coast defence ship | 1st class coast defence ship |
| Naval vessels | Warships | Coast defence ship | 2nd class coast defence ship |
| Naval vessels | Warships | Gunboat | 1st class gunboat |
| Naval vessels | Warships | Gunboat | 2nd class gunboat |
| Naval vessels | Destroyer | Destroyer | 1st class destroyer |
| Naval vessels | Destroyer | Destroyer | 2nd class destroyer |
| Naval vessels | Destroyer | Destroyer | 3rd class destroyer |
| Naval vessels | Submarine | Submarine | 1st class submarine |
| Naval vessels | Submarine | Submarine | 2nd class submarine |
| Naval vessels | Submarine | Submarine | 3rd class submarine |
| Naval vessels | Minesweeper | Minesweeper | |

* Standard classifications of the naval auxiliary vessels

| Auxiliary vessels | Auxiliary vessel | Repair vessel | |
| - | - | - | - |
| Auxiliary vessels | Auxiliary vessel | Transport vessel | |
| Auxiliary vessels | Auxiliary vessel | Icebreaker | |
| Auxiliary vessels | Auxiliary vessel | Survey ship | |
| Auxiliary vessels | Auxiliary vessel | Target ship | |
| Auxiliary vessels | Auxiliary vessel | Auxiliary training ship | |
| Auxiliary vessels | Auxiliary boat | Mine boat | 1st class mine boat |
| Auxiliary vessels | Auxiliary boat | Mine boat | 2nd class mine boat |
| Auxiliary vessels | Auxiliary boat | Mine boat | 3rd class mine boat |
| Auxiliary vessels | Auxiliary boat | Capture-net layer (捕獲網艇, Hokakumōtei) | |
| Auxiliary vessels | Auxiliary boat | Auxiliary minesweeper | 1st class auxiliary minesweeper |
| Auxiliary vessels | Auxiliary boat | Auxiliary minesweeper | 2nd class auxiliary minesweeper |
| Auxiliary vessels | Auxiliary boat | Submarine depot boat | |

### 30 May 1931

* Standard classifications of the naval vessels

| Naval vessels | Warships | Battleship | |
| - | - | - | - |
| Naval vessels | Warships | Cruiser | 1st class cruiser |
| Naval vessels | Warships | Cruiser | 2nd class cruiser |
| Naval vessels | Warships | Aircraft carrier | |
| Naval vessels | Warships | Submarine tender | |
| Naval vessels | Warships | Minelayer | |
| Naval vessels | Warships | Coast defence ship | |
| Naval vessels | Warships | Gunboat | |
| Naval vessels | Warships | Training battleship (練習戦艦, Renshū senkan) | |
| Naval vessels | Warships | Training cruiser (練習巡洋艦, Renshū jun'yōkan) | |
| Naval vessels | Destroyer | Destroyer | 1st class destroyer |
| Naval vessels | Destroyer | Destroyer | 2nd class destroyer |
| Naval vessels | Submarine | Submarine | 1st class submarine |
| Naval vessels | Submarine | Submarine | 2nd class submarine |
| Naval vessels | Torpedo boat | Torpedo boat | |
| Naval vessels | Minesweeper | Minesweeper | |

* Standard classifications of the naval auxiliary vessels

| Auxiliary vessels | Auxiliary vessel | Repair vessel |
| - | - | - |
| Auxiliary vessels | Auxiliary vessel | Transport vessel |
| Auxiliary vessels | Auxiliary vessel | Icebreaker |
| Auxiliary vessels | Auxiliary vessel | Survey ship |
| Auxiliary vessels | Auxiliary vessel | Target ship |
| Auxiliary vessels | Auxiliary vessel | Auxiliary training ship |
| Auxiliary vessels | Auxiliary boat | Mine boat |
| Auxiliary vessels | Auxiliary boat | Auxiliary minesweeper |
| Auxiliary vessels | Auxiliary boat | Submarine depot boat |

### 26 June 1941

* Standard classifications of the naval vessels

| Naval vessels | Warships | Battleship | |
| - | - | - | - |
| Naval vessels | Warships | Cruiser | 1st class cruiser |
| Naval vessels | Warships | Cruiser | 2nd class cruiser |
| Naval vessels | Warships | Aircraft carrier | |
| Naval vessels | Warships | Seaplane tender (水上機母艦, Suijōkibokan) | |
| Naval vessels | Warships | Submarine tender | |
| Naval vessels | Warships | Minelayer | |
| Naval vessels | Warships | Coast defence ship | |
| Naval vessels | Warships | Gunboat | |
| Naval vessels | Warships | Training battleship | |
| Naval vessels | Warships | Training cruiser | |
| Naval vessels | Destroyer | Destroyer | 1st class destroyer |
| Naval vessels | Destroyer | Destroyer | 2nd class destroyer |
| Naval vessels | Submarine | Submarine | 1st class submarine |
| Naval vessels | Submarine | Submarine | 2nd class submarine |
| Naval vessels | Torpedo boat | Torpedo boat | |
| Naval vessels | Minesweeper | Minesweeper | |
| Naval vessels | Submarine chaser (駆潜艇, Kusentei) | Submarine chaser (駆潜艇, Kusentei) | |

* Standard classifications of the naval auxiliary vessels

| Auxiliary vessels | Auxiliary vessel | Repair vessel |
| - | - | - |
| Auxiliary vessels | Auxiliary vessel | Transport vessel |
| Auxiliary vessels | Auxiliary vessel | Icebreaker |
| Auxiliary vessels | Auxiliary vessel | Survey ship |
| Auxiliary vessels | Auxiliary vessel | Target ship |
| Auxiliary vessels | Auxiliary vessel | Auxiliary training ship |
| Auxiliary vessels | Auxiliary boat | Mine boat |
| Auxiliary vessels | Auxiliary boat | Auxiliary submarine chaser (駆潜特務艇, Kusentokumutei) |
| Auxiliary vessels | Auxiliary boat | Auxiliary minesweeper |
| Auxiliary vessels | Auxiliary boat | Patrol boat (哨戒艇, Shōkaitei) |
| Auxiliary vessels | Auxiliary boat | Cable layer (電纜敷設艇, Denranfusetsutei) |
| Auxiliary vessels | Auxiliary boat | Motor torpedo boat (魚雷艇, Gyoraitei) |
| Auxiliary vessels | Auxiliary boat | Submarine depot boat |

### 30 June 1945 (Final)

* Standard classifications of the naval vessels

| Naval vessels | Warships | Battleship | |
| - | - | - | - |
| Naval vessels | Warships | Cruiser | 1st class cruiser |
| Naval vessels | Warships | Cruiser | 2nd class cruiser |
| Naval vessels | Warships | Aircraft carrier | |
| Naval vessels | Warships | Seaplane tender | |
| Naval vessels | Warships | Submarine tender | |
| Naval vessels | Warships | Minelayer | |
| Naval vessels | Warships | Training battleship | |
| Naval vessels | Warships | Training cruiser | |
| Naval vessels | Destroyer | Destroyer | 1st class destroyer |
| Naval vessels | Destroyer | Destroyer | 2nd class destroyer |
| Naval vessels | Submarine | Submarine | 1st class submarine |
| Naval vessels | Submarine | Submarine | 2nd class submarine |
| Naval vessels | Coast defence ship | Coast defence ship | |
| Naval vessels | Gunboat | Gunboat | |
| Naval vessels | Torpedo boat | Torpedo boat | |
| Naval vessels | Minesweeper | Minesweeper | |
| Naval vessels | Submarine chaser | Submarine chaser | |
| Naval vessels | Patrol boat | Patrol boat | |
| Naval vessels | Landing ship (輸送艦, Yusōkan) | Landing ship (輸送艦, Yusōkan) | 1st class landing ship (一等輸送艦, Ittō Yusōkan) |
| Naval vessels | Landing ship (輸送艦, Yusōkan) | Landing ship (輸送艦, Yusōkan) | 2nd class landing ship (二等輸送艦, Nitō Yusōkan) |
| Naval vessels | Mine boat | Mine boat | |

* Standard classifications of the naval auxiliary vessels

| Auxiliary vessels | Auxiliary vessel | Repair vessel |
| - | - | - |
| Auxiliary vessels | Auxiliary vessel | Transport vessel |
| Auxiliary vessels | Auxiliary vessel | Icebreaker |
| Auxiliary vessels | Auxiliary vessel | Survey ship |
| Auxiliary vessels | Auxiliary vessel | Target ship |
| Auxiliary vessels | Auxiliary vessel | Auxiliary training ship |
| Auxiliary vessels | Auxiliary boat | Auxiliary mine boat (敷設特務艇, Fusetsutokumutei) |
| Auxiliary vessels | Auxiliary boat | Auxiliary submarine chaser |
| Auxiliary vessels | Auxiliary boat | Auxiliary patrol boat (哨戒特務艇, Shōkaitokumutei) |
| Auxiliary vessels | Auxiliary boat | Auxiliary minesweeper |
| Auxiliary vessels | Auxiliary boat | Cable layer |
| Auxiliary vessels | Auxiliary boat | Motor torpedo boat |
| Auxiliary vessels | Auxiliary boat | Coast defence boat (海防艇, Kaibōtei) |

## Detailed classification tables

### Battleship

| Date | Top classification | Higher classification | Classification | Lower classification | Note, classification boundary |
| - | - | - | - | - | - |
| 21 March 1898 | Warships | | Battleship | 1st class battleship | And over 10,000 tons designated displacement |
| 21 March 1898 | Warships | | Battleship | 2nd class battleship | Less than 10,000 tons designated displacement |
| 22 June 1900 | Naval Vessels | Warships | Battleship | 1st class battleship | Same as on 21 March 1898 |
| 22 June 1900 | Naval Vessels | Warships | Battleship | 2nd class battleship | Same as on 21 March 1898 |
| 12 December 1905 | Naval vessels | Warships | Battleship | | 'Class' was abolished |

### Battlecruiser

| Date | Top classification | Higher classification | Classification | Lower classification | Note, classification boundary |
| - | - | - | - | - | - |
| 28 August 1912 | Naval Vessels | Warships | Battlecruiser | | |
| 30 May 1931 | | | | | Abolished and unified to battleship |

### Cruiser

| Date | Top classification | Higher classification | Classification | Lower classification | Note, classification boundary |
| - | - | - | - | - | - |
| 21 March 1898 | Warships | | Cruiser | 1st class cruiser | And over 7,000 tons designated displacement |
| 21 March 1898 | Warships | | Cruiser | 2nd class cruiser | And over 3,500 tons designated displacement, less than 7,000 tons designated displacement |
| 21 March 1898 | Warships | | Cruiser | 3rd class cruiser | Less than 3,500 tons designated displacement |
| 22 June 1900 | Naval Vessels | Warships | Cruiser | 1st class cruiser | Same as on 21 March 1898 |
| 22 June 1900 | Naval Vessels | Warships | Cruiser | 2nd class cruiser | Same as on 21 March 1898 |
| 22 June 1900 | Naval Vessels | Warships | Cruiser | 3rd class cruiser | Same as on 21 March 1898 |
| 28 August 1912 | Naval vessels | Warships | Cruiser | 1st class cruiser | And over 7,000 tons designated displacement |
| 28 August 1912 | Naval vessels | Warships | Cruiser | 2nd class cruiser | Less than 7,000 tons designated displacement, '3rd class' was abolished. |
| 31 May 1934 | Naval vessels | Warships | Cruiser | 1st class cruiser | Equipped over 155 mm (6.1 in) gun |
| 31 May 1934 | Naval vessels | Warships | Cruiser | 2nd class cruiser | Equipped and under 155 mm (6.1 in) gun |

### Aircraft carrier

| Date | Top classification | Higher classification | Classification | Lower classification | Note, classification boundary |
| - | - | - | - | - | - |
| 1 April 1920 | Naval Vessels | Warships | Aircraft carrier | | |

### Seaplane tender

| Date | Top classification | Higher classification | Classification | Lower classification | Note, classification boundary |
| - | - | - | - | - | - |
| 31 May 1934 | Naval Vessels | Warships | Seaplane tender | | Independent from aircraft carrier |

### Dispatch vessel

| Date | Top classification | Higher classification | Classification | Note, classification boundary |
| - | - | - | - | - |
| 21 March 1898 | Warships | | Dispatch vessel | Torpedo gunboat was classified to dispatch boat |
| 22 June 1900 | Naval vessels | Warships | Dispatch vessel | |
| 28 August 1912 | | | | Abolished and unified to gunboat |

### Torpedo boat tender/Submarine tender

| Date | Top classification | Higher classification | Classification | Note, classification boundary |
| - | - | - | - | - |
| 21 March 1898 | Warships | | Torpedo boat tender | |
| 22 June 1900 | Naval vessels | Warships | Torpedo boat tender | |
| 28 August 1912 | | | | Abolished and unified to coast defence ship |
| 1 April 1920 | Naval vessels | Warships | Torpedo boat tender | Revived |
| 1 December 1924 | Naval vessels | Warships | Submarine tender | Renamed |

### Minelaying ship/Minelayer/Rapid extension netlayer

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

| Date | Top classification | Higher classification | Classification | Note, classification boundary |
| - | - | - | - | - |
| 17 May 1916 | Auxiliary ships | | Minelaying ship | |
| 1 April 1920 | Naval vessels | Warships | Minelayer | Renamed |
| 2 March 1927 | Naval vessels | Warships | Minelayer | |
| 2 March 1927 | Naval vessels | Warships | Rapid extension netlayer | |
| 22 March 1929 | Naval vessels | Warships | Minelayer | Rapid extension netlayer was abolished, and unified to minelayer |

### Training battleship

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

| Date | Top classification | Higher classification | Classification | Lower classification | Note, classification boundary |
| - | - | - | - | - | - |
| 30 May 1931 | Naval vessels | Warships | Training battleship | | |

### Training cruiser

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

| Date | Top classification | Higher classification | Classification | Lower classification | Note, classification boundary |
| - | - | - | - | - | - |
| 30 May 1931 | Naval vessels | Warships | Training cruiser | | |

### Coast defence ship

| Date | Top classification | Higher classification | Classification | Lower classification | Note, classification boundary |
| - | - | - | - | - | - |
| 21 March 1898 | Warships | | Coast defence ship | 1st class coast defence ship | And over 7,000 tons designated displacement |
| 21 March 1898 | Warships | | Coast defence ship | 2nd class coast defence ship | And over 3,500 tons designated displacement, less than 7,000 tons designated displacement |
| 21 March 1898 | Warships | | Coast defence ship | 3rd class coast defence ship | Less than 3,500 tons displacement |
| 22 June 1900 | Naval vessels | Warships | Coast defence ship | 1st class coast defence ship | Same as on 21 March 1898 |
| 22 June 1900 | Naval vessels | Warships | Coast defence ship | 2nd class coast defence ship | Same as on 21 March 1898 |
| 22 June 1900 | Naval vessels | Warships | Coast defence ship | 3rd class coast defence ship | Same as on 21 March 1898 |
| 28 August 1912 | Naval vessels | Warships | Coast defence ship | 1st class coast defence ship | And over 7,000 tons designated displacement |
| 28 August 1912 | Naval vessels | Warships | Coast defence ship | 2nd class coast defence ship | Less than 7,000 tons designated displacement |
| 30 May 1931 | Naval vessels | Warships | Coast defence ship | | 'Class' was abolished |
| 1 July 1942 | Naval vessels | | Coast defence ship (as Escort ship) | | Armored cruisers were moved to 1st class cruiser or auxiliary training ship |

### Gunboat

| Date | Top classification | Higher classification | Classification | Lower classification | Note, classification boundary |
| - | - | - | - | - | - |
| 21 March 1898 | Warships | | Gunboat | 1st class gunboat | And over 1,000 tons designated displacement |
| 21 March 1898 | Warships | | Gunboat | 2nd class gunboat | Less than 1,000 tons designated displacement |
| 22 June 1900 | Naval vessels | Warships | Gunboat | 1st class gunboat | Same as on 21 March 1898 |
| 22 June 1900 | Naval vessels | Warships | Gunboat | 2nd class gunboat | Same as on 21 March 1898 |
| 28 August 1912 | Naval vessels | Warships | Gunboat | 1st class gunboat | And over 800 tons displacement |
| 28 August 1912 | Naval vessels | Warships | Gunboat | 2nd class gunboat | Less than 800 tons displacement |
| 30 May 1931 | Naval vessels | Warships | Gunboat | | 'Class' was abolished |
| 1 October 1944 | Naval vessels | | Gunboat | | |

### Torpedo boat destroyer/Destroyer

| Date | Top classification | Higher classification | Classification | Lower classification | Note, classification boundary |
| - | - | - | - | - | - |
| 21 March 1898 | Torpedo boat | | Torpedo boat destroyer | | |
| 22 June 1900 | Naval vessels | Warships | Destroyer | | Independent from torpedo boat and renamed |
| 12 December 1905 | Naval vessels | | Destroyer | | |
| 28 August 1912 | Naval vessels | | Destroyer | 1st class destroyer | And over 1,000 tons designated displacement |
| 28 August 1912 | Naval vessels | | Destroyer | 2nd class destroyer | And over 600 tons designated displacement, less than 1,000 tons designated displacement |
| 28 August 1912 | Naval vessels | | Destroyer | 3rd class destroyer | Less than 600 tons designated displacement |
| 30 May 1931 | Naval vessels | | Destroyer | 1st class destroyer | And over 1,000 tons designated displacement |
| 30 May 1931 | Naval vessels | | Destroyer | 2nd class destroyer | Less than 1,000 tons designated displacement, '3rd class' was abolished |
| 31 May 1934 | Naval vessels | | Destroyer | 1st class destroyer | And over 1,000 tons standard displacement |
| 31 May 1934 | Naval vessels | | Destroyer | 2nd class destroyer | Less than 1,000 tons standard displacement |

### 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.

| Date | Top classification | Classification | Lower classification | Note, classification boundary |
| - | - | - | - | - |
| 23 January 1905 | Torpedo boat | Submersible | | |
| 12 December 1905 | Naval vessels | Submersible | | Independent from torpedo boat |
| 28 August 1912 | Naval vessels | Submersible | 1st class submersible | And over 600 tons surfaced displacement |
| 28 August 1912 | Naval vessels | Submersible | 2nd class submersible | Less than 600 tons surfaced displacement |
| 4 April 1919 | Naval vessels | Submarine | 1st class submarine | Renamed; and over 1,000 tons surfaced displacement |
| 4 April 1919 | Naval vessels | Submarine | 2nd class submarine | Renamed, and over 600 tons surfaced displacement, less than 1,000 tons surfaced displacement |
| 4 April 1919 | Naval vessels | Submarine | 3rd class submarine | Less than 600 tons surfaced displacement |
| 30 May 1931 | Naval vessels | Submarine | 1st class submarine | And over 1,000 tons surfaced displacement |
| 30 May 1931 | Naval vessels | Submarine | 2nd class submarine | Less than 1,000 tons surfaced displacement, '3rd class' was abolished |

### Torpedo boat

| Date | Top classification | Higher classification | Classification | Lower classification | Note, classification boundary |
| - | - | - | - | - | - |
| 13 August 1890 | Naval ships | Category 'B' warship | Torpedo boat | | |
| 19 October 1893 | Naval ships | Category 'B' warship | Torpedo boat | 1st class torpedo boat | And over 70 tons displacement |
| 19 October 1893 | Naval ships | Category 'B' warship | Torpedo boat | 2nd class torpedo boat | And over 20 tons designated displacement, less than 70 tons designated displacement |
| 19 October 1893 | Naval ships | Category 'B' warship | Torpedo boat | 3rd class torpedo boat | Less than 20 tons designated displacement (vedette boat) |
| 28 March 1896 | Naval ships | | Torpedo boat | 1st class torpedo boat | Same as on 19 October 1893 |
| 28 March 1896 | Naval ships | | Torpedo boat | 2nd class torpedo boat | Same as on 19 October 1893 |
| 28 March 1896 | Naval ships | | Torpedo boat | 3rd class torpedo boat | Same as on 19 October 1893 |
| 21 March 1898 | | | Torpedo boat | Torpedo boat destroyer | |
| 21 March 1898 | | | Torpedo boat | 1st class torpedo boat | And over 120 tons designated displacement |
| 21 March 1898 | | | Torpedo boat | 2nd class torpedo boat | And over 70 tons designated displacement, less than 120 tons designated displacement |
| 21 March 1898 | | | Torpedo boat | 3rd class torpedo boat | And over 20 tons designated displacement, less than 70 tons designated displacement |
| 21 March 1898 | | | Torpedo boat | 4th class torpedo boat | Less than 20 tons designated displacement (vedette boat) |
| 22 June 1900 | Naval vessels | | Torpedo boat | 1st class torpedo boat | Same as on 21 March 1898; Torpedo boat destroyer was independent from torpedo boat, and renamed destroyer. |
| 22 June 1900 | Naval vessels | | Torpedo boat | 2nd class torpedo boat | Same as on 21 March 1898; Torpedo boat destroyer was independent from torpedo boat, and renamed destroyer. |
| 22 June 1900 | Naval vessels | | Torpedo boat | 3rd class torpedo boat | Same as on 21 March 1898; Torpedo boat destroyer was independent from torpedo boat, and renamed destroyer. |
| 22 June 1900 | Naval vessels | | Torpedo boat | 4th class torpedo boat | Same as on 21 March 1898; Torpedo boat destroyer was independent from torpedo boat, and renamed destroyer. |
| 23 January 1905 | Naval vessels | | Torpedo boat | 1st class torpedo boat | Same as on 21 March 1898 |
| 23 January 1905 | Naval vessels | | Torpedo boat | 2nd class torpedo boat | Same as on 21 March 1898 |
| 23 January 1905 | Naval vessels | | Torpedo boat | 3rd class torpedo boat | Same as on 21 March 1898 |
| 23 January 1905 | Naval vessels | | Torpedo boat | 4th class torpedo boat | Same as on 21 March 1898 |
| 23 January 1905 | Naval vessels | | Torpedo boat | Submersible | IJN called Special-Torpedo boat (特号水雷艇, Tokugō-Suiraitei) for counterintelligence |
| 12 December 1905 | Naval vessels | | Torpedo boat | 1st class torpedo boat | Same as on 21 March 1898 Submersible was independent from torpedo boat. |
| 12 December 1905 | Naval vessels | | Torpedo boat | 2nd class torpedo boat | Same as on 21 March 1898 Submersible was independent from torpedo boat. |
| 12 December 1905 | Naval vessels | | Torpedo boat | 3rd class torpedo boat | Same as on 21 March 1898 Submersible was independent from torpedo boat. |
| 12 December 1905 | Naval vessels | | Torpedo boat | 4th class torpedo boat | Same as on 21 March 1898 Submersible was independent from torpedo boat. |
| 28 August 1912 | Naval vessels | | Torpedo boat | 1st class torpedo boat | And over 120 tons designated displacement |
| 28 August 1912 | Naval vessels | | Torpedo boat | 2nd class torpedo boat | Less than 120 tons designated displacement |
| 15 January 1924 | | | | | Abolished |
| 30 May 1931 | Naval vessels | | Torpedo boat | | Revived by the London Naval Treaty |

### Mine boat/Capture-net layer

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

| Date | Top classification | Higher classification | Classification | Lower classification | Note, classification boundary |
| - | - | - | - | - | - |
| 1 July 1920 | Auxiliary vessels | Auxiliary boat | Mine boat | 1st class mine boat | And over 800 tons displacement |
| 1 July 1920 | Auxiliary vessels | Auxiliary boat | Mine boat | 2nd class mine boat | And over 400 tons designated displacement, less than 800 tons designated displacement |
| 1 July 1920 | Auxiliary vessels | Auxiliary boat | Mine boat | 3rd class mine boat | Less than 400 tons designated displacement |
| 2 March 1927 | Auxiliary vessels | Auxiliary boat | Mine boat | 1st class mine boat | Same as on 1 July 1920 |
| 2 March 1927 | Auxiliary vessels | Auxiliary boat | Mine boat | 2nd class mine boat | Same as on 1 July 1920 |
| 2 March 1927 | Auxiliary vessels | Auxiliary boat | Mine boat | 3rd class mine boat | Same as on 1 July 1920 |
| 2 March 1927 | Auxiliary vessels | Auxiliary boat | Capture-net layer | | |
| 22 March 1929 | Auxiliary vessels | Auxiliary boat | Mine boat | 1st class mine boat | Same as on 1 July 1920; capture-net layer was abolished and unified to mine boat |
| 22 March 1929 | Auxiliary vessels | Auxiliary boat | Mine boat | 2nd class mine boat | Same as on 1 July 1920; capture-net layer was abolished and unified to mine boat |
| 22 March 1929 | Auxiliary vessels | Auxiliary boat | Mine boat | 3rd class mine boat | Same as on 1 July 1920; capture-net layer was abolished and unified to mine boat |
| 30 May 1931 | Auxiliary vessels | Auxiliary boat | Mine boat | | 'Class' was abolished |
| 1 February 1944 | Naval vessels | | Mine boat | | |

### Auxiliary minelayer

| Date | Top classification | Higher classification | Classification | Lower classification | Note, classification boundary |
| - | - | - | - | - | - |
| 1 February 1944 | Auxiliary vessels | Auxiliary boat | Auxiliary minelayer | | Divided from mine boat |

### Cable layer

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

| Date | Top classification | Higher classification | Classification | Lower classification | Note, classification boundary |
| - | - | - | - | - | - |
| 25 October 1940 | Auxiliary vessels | Auxiliary boat | Cable layer | | Independent from miscellaneous ship |

### Minesweeper

| Date | Top classification | Higher classification | Classification | Lower classification | Note, classification boundary |
| - | - | - | - | - | - |
| 1 April 1920 | Auxiliary vessels | Auxiliary boat | Minesweeper | 1st class minesweeper | And over 500 tons designated displacement |
| 1 April 1920 | Auxiliary vessels | Auxiliary boat | Minesweeper | 2nd class minesweeper | Less than 500 tons designated displacement |
| 30 June 1923 | Naval vessels | | Minesweeper | | 'Class' was abolished |

### Auxiliary minesweeper

| Date | Top classification | Higher classification | Classification | Lower classification | Note, classification boundary |
| - | - | - | - | - | - |
| 30 June 1923 | Auxiliary vessels | Auxiliary boat | Auxiliary minesweeper | 1st class auxiliary minesweeper | And over 500 tons designated displacement |
| 30 June 1923 | Auxiliary vessels | Auxiliary boat | Auxiliary minesweeper | 2nd class auxiliary minesweeper | Less than 500 tons designated displacement |
| 30 May 1931 | Auxiliary vessels | Auxiliary boat | Auxiliary minesweeper | | 'Class' was abolished |

### Submarine chaser

| Date | Top classification | Higher classification | Classification | Lower classification | Note, classification boundary |
| - | - | - | - | - | - |
| 23 May 1933 | Auxiliary vessels | Auxiliary boat | Submarine chaser | | |
| 1 April 1940 | Naval vessels | | Submarine chaser | | |

### Auxiliary submarine chaser

| Date | Top classification | Higher classification | Classification | Lower classification | Note, classification boundary |
| - | - | - | - | - | - |
| 1 April 1940 | Auxiliary vessels | Auxiliary boat | Auxiliary submarine chaser | | Divided from submarine chaser |

### Patrol boat

| Date | Top classification | Higher classification | Classification | Lower classification | Note, classification boundary |
| - | - | - | - | - | - |
| 30 March 1940 | Auxiliary vessels | Auxiliary boat | Patrol boat | | |
| 15 February 1943 | Naval vessels | | Patrol boat | | |

### Auxiliary patrol boat

| Date | Top classification | Higher classification | Classification | Lower classification | Note, classification boundary |
| - | - | - | - | - | - |
| 15 February 1943 | Auxiliary vessels | Auxiliary boat | Auxiliary patrol boat | | Divided from patrol boat |

### Landing ship

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

| Date | Top classification | Higher classification | Classification | Lower classification | Note, classification boundary |
| - | - | - | - | - | - |
| 5 February 1944 | Naval vessels | | Landing ship | 1st class landing ship | And over 1,000 tons displacement |
| 5 February 1944 | Naval vessels | | Landing ship | 2nd class landing ship | Less than 1,000 tons designated displacement |

### Motor torpedo boat

| Date | Top classification | Higher classification | Classification | Lower classification | Note, classification boundary |
| - | - | - | - | - | - |
| 30 June 1941 | Auxiliary vessels | Auxiliary boat | Motor torpedo boat | | Independent from miscellaneous ship |

### Coast defence boat

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

| Date | Top classification | Higher classification | Classification | Lower classification | Note, classification boundary |
| - | - | - | - | - | - |
| 30 June 1945 | Auxiliary vessels | Auxiliary boat | Coast defence boat | | |

### Repair ship/Repair vessel

| Date | Top classification | Higher classification | Classification | Note, classification boundary |
| - | - | - | - | - |
| 12 December 1905 | | | Repair ship | |
| 17 May 1916 | Auxiliary ships | | Repair ship | |
| 1 April 1920 | Auxiliary vessels | Auxiliary vessel | Repair vessel | Renamed, small sized repair ships were moved to miscellaneous ship |

### 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).

| Date | Top classification | Higher classification | Classification | Note, classification boundary |
| - | - | - | - | - |
| 5 October 1872 | Transport vessel | | 4th class transport vessel | And over 800 tons displacement |
| 5 October 1872 | Transport vessel | | 5th class transport vessel | And over 500 tons displacement |
| 5 October 1872 | Transport vessel | | 6th class transport vessel | And over 200 tons displacement |
| 5 October 1872 | Transport vessel | | 7th class transport vessel | And under 200 tons displacement |
| 13 August 1890 | Vessels | Category 'D' warship | Transport ship | |
| 1 April 1896 | Vessels | Miscellaneous ships | Transport ship | |
| 12 December 1905 | | | Transport ship | Independent from miscellaneous ships |
| 17 May 1916 | Auxiliary ships | | Transport ship | |
| 1 April 1920 | Auxiliary vessels | Auxiliary vessel | Transport vessel | |

### Hospital ship

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

| Date | Top classification | Higher classification | Classification | Lower classification | Note, classification boundary |
| - | - | - | - | - | - |
| 12 December 1905 | | | Hospital ship | | |
| 17 May 1916 | | | | | Abolished |

### Icebreaker

* Note; pertinence of icebreaker was only Ōtomari.

| Date | Top classification | Higher classification | Classification | Lower classification | Note, classification boundary |
| - | - | - | - | - | - |
| 3 August 1921 | Auxiliary vessels | Auxiliary vessel | Icebreaker | | |

### Survey ship

| Date | Top classification | Higher classification | Classification | Lower classification | Note, classification boundary |
| - | - | - | - | - | - |
| 31 March 1922 | Auxiliary vessels | Auxiliary vessel | Survey ship | | |

### Target ship

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

| Date | Top classification | Higher classification | Classification | Lower classification | Note, classification boundary |
| - | - | - | - | - | - |
| 29 September 1923 | Auxiliary vessels | Auxiliary vessel | Target ship | | |

### Auxiliary training ship

| Date | Top classification | Higher classification | Classification | Lower classification | Note, classification boundary |
| - | - | - | - | - | - |
| 30 November 1922 | Auxiliary vessels | Auxiliary vessel | Auxiliary training ship | | |

### Submarine depot boat

| Date | Top classification | Higher classification | Classification | Lower classification | Note, classification boundary |
| - | - | - | - | - | - |
| 1 July 1920 | Auxiliary vessels | Auxiliary boat | Submarine depot boat | | Moved from miscellaneous ship |
| between 1 July 1942–30 September 1944 | | | | | Abolished |

## Appendix

### 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)

| Steamship (汽船, Kisen) | And over 250 tons displacement, and less 400 tons displacement | And over 250 tons displacement, and less 400 tons displacement |
| - | - | - |
| 150 tons displacement ||
| 80 tons displacement ||
| 60 tons displacement ||
| 35 tons displacement ||
| 16 tons displacement ||
| 12.5 tons displacement ||
| And less 10 tons displacement ||
| Boat (端舟, Hashibune) | 38 feet launch | 38 feet launch |
| 32 feet pinnace ||
| 30 feet cutter ||
| 28 feet cutter ||
| 26 feet cutter ||
| 23 feet cutter ||
| 30 feet gig ||
| 27 feet gig ||
| 25 feet gig ||
| Yard auxiliary ship (雑船, Zatsusen) | Rigged torpedo boat (帆装水雷船, Hansō suiraisen) | Rigged torpedo boat (帆装水雷船, Hansō suiraisen) |
| Dredger (泥浚船, Deishunsen) ||
| Mechanical dredger (泥浚器船, Deishunkisen); dipper dredger, bucket dredger, grab dredger and pump dredger ||
| Drilling ship (岩砕船, Gansaisen) ||
| Yard auxiliary ship (雑船, Zatsusen) | Water supply ship (水船, Suisen) | Steamer (汽走, Kisō); and over 150 tons loadage, and less 300 tons loadage |
| Yard auxiliary ship (雑船, Zatsusen) | Water supply ship (水船, Suisen) | Western style ship (西洋形, Seiyōgata); and over 100 tons loadage, and less 200 tons loadage |
| Yard auxiliary ship (雑船, Zatsusen) | Water supply ship (水船, Suisen) | Japanese style ship (和形, Wagata); and over 10 tons loadage, and less 30 tons loadage |
| Barge (運貨船, Unkasen); And over 50 tons loadage, and less 100 tons loadage ||
| Coal supply ship (石炭船, Sekitansen); And over 50 tons loadage, and less 150 tons loadage ||
| Lighter (五大力船, Godairikisen); And over 20 tons loadage, and less 30 tons loadage ||
| Hopper barge (泥受船, Doroukesen) ||
| Junk (伝馬船, Tenmasen) ||
| High-speed oars (押送船, Oshokurisen) ||
| Floating pier (足場船, Ashibasen); And over 30 feet, and less 46 feet ||
| Dumper (塵芥船, Jinkaisen) ||
| Yard auxiliary ship (雑船, Zatsusen) | Floating crane (起重器船, Kijūkisen) | 50 tons ability |
| Yard auxiliary ship (雑船, Zatsusen) | Floating crane (起重器船, Kijūkisen) | 15 tons ability |
| Floating drydock (浮船渠, Ukisenkyo) ||
| Pile driver (杭打器船, Kuiuchikisen) ||
| Pontoon (橋船, Kyōsen) ||
| Training ship (練習船, Renshūsen) ||

### Converted merchant ship classification tables

**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)

| Converted merchant vessels (特設艦船, Tokusetsu kansen) | Converted merchant cruiser (特設巡洋艦, Tokusetsu jun'yōkan) | |
| - | - | - |
| Converted merchant vessels (特設艦船, Tokusetsu kansen) | Converted merchant torpedo recovery ship (特設水雷母艦, Tokusetsu suiraibokan) | |
| Converted merchant vessels (特設艦船, Tokusetsu kansen) | Converted merchant air group carrier (特設航空隊母艦, Tokusetsu kōkūtaibokan) | |
| Converted merchant vessels (特設艦船, Tokusetsu kansen) | Converted merchant minesweeper division depot ship (特設掃海隊母艦, Tokusetsu sōkaitaibokan) | |
| Converted merchant vessels (特設艦船, Tokusetsu kansen) | Converted merchant gunboat (特設砲艦, Tokusetsu hōkan) | |
| Converted merchant vessels (特設艦船, Tokusetsu kansen) | Converted merchant minesweeper (特設掃海艇, Tokusetsu sōkaitei) | |
| Converted merchant vessels (特設艦船, Tokusetsu kansen) | Converted merchant repair ship (特設工作船, Tokusetsu kōsakusen) | |
| Converted merchant vessels (特設艦船, Tokusetsu kansen) | Converted merchant transport ship (特設運送船, Tokusetsu unsōsen) | Munition and ammunition ship (給兵船, Kyūheisen) |
| Converted merchant vessels (特設艦船, Tokusetsu kansen) | Converted merchant transport ship (特設運送船, Tokusetsu unsōsen) | Water supply ship (給水船, Kyūsuisen) |
| Converted merchant vessels (特設艦船, Tokusetsu kansen) | Converted merchant transport ship (特設運送船, Tokusetsu unsōsen) | Food supply ship (給糧船, Kyūryōsen) |
| Converted merchant vessels (特設艦船, Tokusetsu kansen) | Converted merchant transport ship (特設運送船, Tokusetsu unsōsen) | Collier (給炭船, Kyūtansen) |
| Converted merchant vessels (特設艦船, Tokusetsu kansen) | Converted merchant transport ship (特設運送船, Tokusetsu unsōsen) | Oiler (給油船, Kyūyusen) |
| Converted merchant vessels (特設艦船, Tokusetsu kansen) | Converted merchant transport ship (特設運送船, Tokusetsu unsōsen) | Communication ship (通信船, Tsūshinsen) |
| Converted merchant vessels (特設艦船, Tokusetsu kansen) | Converted merchant transport ship (特設運送船, Tokusetsu unsōsen) | Freighter (雑用船, Zatsuyōsen) |
| Converted merchant vessels (特設艦船, Tokusetsu kansen) | Converted merchant cable layer (特設電線敷設船, Tokusetsu densenfusetsusen) | |
| Converted merchant vessels (特設艦船, Tokusetsu kansen) | Converted merchant hospital ship (特設病院船, Tokusetsu byōinsen) | |
| Converted merchant vessels (特設艦船, Tokusetsu kansen) | Converted merchant salvage ship (特設救難船, Tokusetsu kyūnansen) | |

**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)

| Converted merchant vessels | Converted merchant warship (特設軍艦, Tokusetsu gunkan) | Converted merchant cruiser | |
| - | - | - | - |
| Converted merchant vessels | Converted merchant warship (特設軍艦, Tokusetsu gunkan) | Converted merchant minelayer (特設敷設艦, Tokusetsu fusetsukan) | |
| Converted merchant vessels | Converted merchant warship (特設軍艦, Tokusetsu gunkan) | Converted merchant rapid extension netlayer (特設急設網艦, Tokusetsu kyūsetsumōkan) | |
| Converted merchant vessels | Converted merchant warship (特設軍艦, Tokusetsu gunkan) | Converted merchant aircraft carrier (特設航空母艦, Tokusetsu kōkūbokan) | |
| Converted merchant vessels | Converted merchant warship (特設軍艦, Tokusetsu gunkan) | Converted merchant seaplane tender (特設水上機母艦, Tokusetsu suijōkibokan) | |
| Converted merchant vessels | Converted merchant warship (特設軍艦, Tokusetsu gunkan) | Converted merchant aircraft transport ship (特設航空機運搬艦, Tokusetsu kōkūki unpankan) | |
| Converted merchant vessels | Converted merchant warship (特設軍艦, Tokusetsu gunkan) | Converted merchant torpedo recovery ship | |
| Converted merchant vessels | Converted merchant warship (特設軍艦, Tokusetsu gunkan) | Converted merchant submarine tender (特設潜水母艦, Tokusetsu sensuibokan) | |
| Converted merchant vessels | Converted merchant warship (特設軍艦, Tokusetsu gunkan) | Converted merchant minesweeper tender (特設掃海母艦, Tokusetsu sōkaibokan) | |
| Converted merchant vessels | Converted merchant warship (特設軍艦, Tokusetsu gunkan) | Converted merchant gunboat | |
| Converted merchant vessels | Converted merchant auxiliary boat (特設特務艇, Tokusetsu tokumutei) | Converted merchant capture-net layer (特設捕獲網艇, Tokusetsu hokakumōtei) | |
| Converted merchant vessels | Converted merchant auxiliary boat (特設特務艇, Tokusetsu tokumutei) | Converted merchant anti-submarine net layer (特設防潜網艇, Tokusetsu bōsenmōtei) | |
| Converted merchant vessels | Converted merchant auxiliary boat (特設特務艇, Tokusetsu tokumutei) | Converted merchant mine boat (特設敷設艇, Tokusetsu fusetsutei) | |
| Converted merchant vessels | Converted merchant auxiliary boat (特設特務艇, Tokusetsu tokumutei) | Converted merchant submarine chaser (特設駆潜艇, Tokusetsu kusentei) | |
| Converted merchant vessels | Converted merchant auxiliary boat (特設特務艇, Tokusetsu tokumutei) | Converted merchant minesweeper | |
| Converted merchant vessels | Converted merchant auxiliary boat (特設特務艇, Tokusetsu tokumutei) | Converted merchant picket boat (特設監視艇, Tokusetsu kanshitei) | |
| Converted merchant vessels | Converted merchant auxiliary vessels (特設特務艦船, Tokusetsu tokumukansen) | Converted merchant transport vessel (特設運送艦, Tokusetsu unsōkan) | |
| Converted merchant vessels | Converted merchant auxiliary vessels (特設特務艦船, Tokusetsu tokumukansen) | Converted merchant transport ship | Munition and ammunition ship |
| Converted merchant vessels | Converted merchant auxiliary vessels (特設特務艦船, Tokusetsu tokumukansen) | Converted merchant transport ship | Water supply ship |
| Converted merchant vessels | Converted merchant auxiliary vessels (特設特務艦船, Tokusetsu tokumukansen) | Converted merchant transport ship | Food supply ship |
| Converted merchant vessels | Converted merchant auxiliary vessels (特設特務艦船, Tokusetsu tokumukansen) | Converted merchant transport ship | Collier |
| Converted merchant vessels | Converted merchant auxiliary vessels (特設特務艦船, Tokusetsu tokumukansen) | Converted merchant transport ship | Oiler |
| Converted merchant vessels | Converted merchant auxiliary vessels (特設特務艦船, Tokusetsu tokumukansen) | Converted merchant transport ship | Collier-oiler (給炭油船, Kyūtan'yusen) |
| Converted merchant vessels | Converted merchant auxiliary vessels (特設特務艦船, Tokusetsu tokumukansen) | Converted merchant transport ship | Communication ship |
| Converted merchant vessels | Converted merchant auxiliary vessels (特設特務艦船, Tokusetsu tokumukansen) | Converted merchant transport ship | Freighter |
| Converted merchant vessels | Converted merchant auxiliary vessels (特設特務艦船, Tokusetsu tokumukansen) | Converted merchant repair vessel (特設工作艦, Tokusetsu kōsakukan) | |
| Converted merchant vessels | Converted merchant auxiliary vessels (特設特務艦船, Tokusetsu tokumukansen) | Converted merchant harbor service vessel (特設港務艦, Tokusetsu kōmukan) | |
| Converted merchant vessels | Converted merchant auxiliary vessels (特設特務艦船, Tokusetsu tokumukansen) | Converted merchant survey vessel (特設測量艦, Tokusetsu sokuryōkan) | |
| Converted merchant vessels | Converted merchant auxiliary vessels (特設特務艦船, Tokusetsu tokumukansen) | Converted merchant icebreaker (特設砕氷船, Tokusetsu saihyōsen) | |
| Converted merchant vessels | Converted merchant auxiliary vessels (特設特務艦船, Tokusetsu tokumukansen) | Converted merchant cable layer | |
| Converted merchant vessels | Converted merchant auxiliary vessels (特設特務艦船, Tokusetsu tokumukansen) | Converted merchant hospital ship | |
| Converted merchant vessels | Converted merchant auxiliary vessels (特設特務艦船, Tokusetsu tokumukansen) | Converted merchant salvage ship | |
| Converted merchant vessels | Converted merchant auxiliary vessels (特設特務艦船, Tokusetsu tokumukansen) | Converted merchant miscellaneous ship (特設雑役船, Tokusetsu zatsuekisen) | |

## Footnotes

* ↑ Monthly Ships of the world No. 500, p. 371
* ↑ JACAR C08050092300, p. 2
