Ships, Officers, and Commands, Imperial Japanese Navy, World War II

• Combined Fleet and Area Fleets
• Fleets
• Air Fleets
• Battle Squadrons
• Carrier Divisions
• Destroyer Squadrons
• Destroyer Divisions
• Submarine Squadrons
• Submarine Divisions
• Miscellaneous Units
• Escort Forces
◦ Carrier Air Groups
◦ Combined Naval Air Groups
◦ Naval Air Groups
▫ Naval Districts
▫ Base Forces

▪ Battleships
▪ Aircraft Carriers
▪ Seaplane Carriers and Tenders
▪ Flying Boat Tenders
Cruisers
▪ Heavy Cruisers
▪ Light Cruisers
▪ Armored Cruisers
▪ Armed Merchant Cruisers
Destroyers
▪ 1st Class (Fleet Destroyers)
▪ 2nd Class (Escort Destroyers)
Submarines
▪ 1st Class ("I" Submarines)
▪ 2nd Class ("RO" Submarines)
▪ 3rd Class ("HA" Submarines)
▪ Midget Submarines

Mine Craft
▪ Minelayers
▪ Converted Minelayers
▪ Minesweepers
▪ Converted Minesweepers
▪ Converted Netlayers
Patrol Craft
▪ Patrol Escorts
▪ Patrol Boats
▪ Converted Patrol Boats
▪ Torpedo Boats
▪ Gunboats
▪ Converted Gunboats
▪ River Gunboats
▪ Submarine Chasers
▪ Converted Submarine Chasers

Auxiliary Vessels
▪ Destroyer Tenders
▪ Submarine Tenders
▪ Patrol Craft Tenders
▪ Mine Craft Tenders
▪ Fleet Oilers
▪ Tankers
▪ Colliers
▪ Transports
▪ Store Ships
▪ Ammunition Ships
▪ Aircraft Transports
▪ Repair Ships
▪ Salvage Ships
▪ Water Distillers
▪ Landing Ships
▪ Miscellaneous Vessels

Japanese Shipbuilders

Indexes of Etajima Naval Academy
♦ Graduates by Class Numbers
♦ Graduates by Names [1]

[1] Note: Page size is 2831 KB, as there are over 10,000 names indexed — for convenience — on one page.

Operational histories and day-by-day status records (Tabular Movement Records [TROMs]) of IJN ships can be found at the Nihon Kaigun site, specifically:

Battleships
by Bob Hackett and Sander Kingsepp

Fleet Carriers, Escort Carriers and Seaplane Carriers
by A.P. "Tony" Tully

Heavy Cruisers | Light Cruisers | Ex-Armored Cruisers
by Bob Hackett with Sander Kingsepp

Destroyers | Torpedo Boats
by Allyn D. Nevitt

Submarines | Midget Subs | Midget Sub Carriers | Sub Depot Ships
by Bob Hackett with Sander Kingsepp

Merchant Auxiliaries
by Bob Hackett, Sander Kingsepp, and Peter Cundall

Smaller regular IJN and Converted combatants
by Bob Hackett, Sander Kingsepp, Peter Cundall, and Gilbert Casse

Furthermore, an honorable mention and my thanks to those who have knowingly or unknowingly assisted in this endeavor.

Jeff Donahoo, who provided much of the raw data.

Steve Eckardt and his Imperial Japanese Navy Submarines

Matthew Jones, who has added missing bits and pieces.

Gengoro S. Toda and his Imperial Japanese Navy Tokusetsukansen

Status of Ships:

1st Reserve:
Crew reduced for replenishment and other administrative/budgetary reasons. Carrying a complete armament and working machinery, the vessel was ready to join the fleet, but not included in the Combined Fleet roster. This measure often precluded (or concluded) an extensive overhaul.

2nd Reserve:
Minor refits, repairs, and maintenance works, not necessarily conducted at the home port. The crew was reduced by 20 per cent. Vessel not operational.

3rd Reserve:
Extensive overhaul, conversion or modernization at the home port. The crew was reduced by 50 per cent. Vessel not operational.

4th Reserve:
Major repair or extensive modernization at the home port. The armament was mostly landed. The crew was reduced by at 80 per cent, maintenance conducted by shore personnel. Vessel not operational for a substantial period.
Following the outbreak of the war the 4th Reserve was sometimes used for a lost vessel as an administrative measure preceding the reassignment of its survivors, and before the removal of that vessel from the Naval List.

With thanks to Sander Kingsepp