Imperial Japanese Navy Basic Design
Designations

Bibliography:
Japanese Cruisers of the Pacific War

As allocated by the Basic Design 基本計画 (Kihon Keikaku) Section of the Shipbuilding Section of the Navy Technical Department from 1900 onwards:

Vessel Types:

A: Battleships
B: Battle cruisers
C: Cruisers
E: Gunboats and kaibokan
F: Destroyers and Torpedo Boats
G: Aircraft Carriers
H: Mine-layers
I: Mine-sweepers
J: Special-service vessels
K: Submarine chasers
S: Submarines.

Numbers:

The number indicates in chronological order, each successive design made by the IJN's Design Section for that class of vessel; e.g G-18 is the 18th successive design put forth for an aircraft carrier.

Known Designations

Battleships
A-30: Kawachi
A-102:
Nagato
A-127:
Tosa
A-140: Initial
Yamato Design (10 March 1935)
A-140F5 or F6: Final
Yamato Design
A-150: So called
Super” Yamato
Battlecruisers
B-65:
Cruisers
C-33: Tenryu CL
C-37:
Mogami CA
C-38:
Tone CA
C-41:
Agano CL
C-42:
Oyodo CL
C-44:
Kai-Agano CL
C-46:
Ibuki CA
Aircraft Carriers
G-14: Taiho Derivative
G-15:
Taiho Derivative
Destroyers
F-43: Fubuki (I) Class
F-45:
Hatsuharu Class
F-55:
Matsu and/or Tachibana Class, not known which ones each designation belongs to
F-55B:
Matsu and/or Tachibana Class, not known which ones each designation belongs to