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Japanese Aircraft Designations 1939-1945

by Randy Wilson
Copyright 1997 by Randy Wilson

This document was originally written as an informal guide for AAHM docents. It has not been otherwise published in print, as of this date.

Like the U.S., Japan's Army and Navy each had their own systems of aircraft designation, in some cases as many as four or five systems! Because of this confusion, the Allied forces started assigning code names to each Japanese type, and it is these code names that are most often remembered now.

We will begin by looking at the Imperial Japanese Navy's (IJN) designation systems, as our (Confederate Air Force) Zero and Tora aircraft are all IJN aircraft or replicas.

Japanese Navy Aircraft Designations

At the beginning of World War II, the Japanese Navy Air Force (JNAF) used three different systems to designate their aircraft: one, the Shi number; two, a type number system and three, a type/model/manufacturer code (called the short designation). Later during the war, two new systems were added, popular names and the Service Airplane Development Program (SADP) system.

Experimental Shi Numbers

Every new design, real or projected, from 1931 onward received an experimental or Shi number derived from the current year of the Japanese imperial reign, which for emperor Hirohito began in 1926 and was called Showa. Added to the Shi number was the purpose of the new design, (i.e. carrier fighter, carrier bomber, etc.) to differentiate between different designs. Thus, the Zero was designed to meet a 1937 specification called the 12-shi carrier fighter, that year being the twelfth year of Showa.

Type and Model Number System

Each type of aircraft entering production for the JNAF after 1920 was given a type number combined with a brief description of its primary function. Initially related to Showa dates, in 1929 the type number became the last two digits of the year in the Japanese calendar year. Thus the Aichi dive-bomber which entered production in 1939 (2599 in the Japanese system) was the Type 99 Carrier Bomber. Only a single digit was used when the year ended in 00, as with the Type 0 Carrier Fighter (thus the name "Zero") which entered production in 1940 or the Japanese year 2600.

Subtypes and new versions of a type were indicated by model numbers added after the type. By the late 1930s, model numbers had evolved to two digits beginning with 11 for the first version, indicating the first airframe version and the first powerplant configuration. Thus the Type 0 Carrier Fighter Model 11 was the original production Zero, while the Model 21 was the next production version, with the addition of folding wing tips (thus the "2" for airframe modification in 21). The Type 0 Carrier Fighter Model 52 was the Zero after 5 major airframe and 2 engine configurations.

Further modifications to model numbers were indicated by the Japanese characters Ko, Otsu, Hei, etc. which are normally displayed as lower case Roman letters "a", "b", "c", etc. (i.e. Navy Type 0 Carrier Fighter Model 52c).

Short Designation by Type and Manufacturer

In the late 1920s, the IJN designed an aircraft designation system remarkably similar to that used by the U.S. Navy from 1922 until 1962. Each new design was given a "short designation" consisting of a group of Roman letters and numbers. The first letter (sometimes two) indicated the basic type or purpose of the aircraft, as indicated in the following table:

Basic Type Letters
Letter(s) Basic Type
A Carrier Fighter
B Carrier Attack Bomber (i.e. Torpedo or Level Bomber)
C Reconnaissance
D Carrier Bomber (i.e. Dive Bomber)
E Reconnaissance Seaplane
F Observation Seaplane
G Attack Bomber
H Flying Boat
J Land-based Fighter
K Trainer
L Transport
M Special Floatplane
MX Special Purpose Aircraft
N Fighter Seaplane
P Bomber
Q Patrol Plane
R Land-based Reconnaissance
S Night Fighter

Following the type came a series number indicating the number of major sub-types produced by that manufacturer. Unlike USN practice, the digit "1" was not ignored in this system and was included. Thus the designation G4M designated the fourth attack bomber (G4) designed or produced by Mitsubishi (M, see below).

The second letter was, as indicated above, the manufacturer's code, and included some non-Japanese companies, as shown in the table below:

Manufacturer's Codes
Letter(s) Manufacturer
A Aichi (Aichi Tokei Denki and Aichi Kokuki)
North American Aviation (US)
B Boeing Aircraft (US)  
C Consolidated Aircraft (US)
D Douglas Aircraft (US)
G Hitachi Kokuki
Grumman Aircraft Engineering (US)
H Hiro (Dai-Juichi Kaigun Koskusho)
Hawker Aircraft (UK)
He Ernst Heinkel Flugzeugwerke (GER)
J Nihon Kogata Hikoki
Junkers Flugzeug und Moterenwerke (GER)
K Kawanishi Kokuki
Kinner Airplane & Motor (US)
M Mitsubishi Jukogyo
N Nakajima Hikoki
P Nihon Hikoki
S Sasebo (Dai-Nijuichi Kaigun Kokusho)
Si Showa Hikoki
V Vought-Sikorsky (US)
W Watanabe Tekkosho
Kyushu Hikoki
Y Yokosuka (Dai-Ichi Kaigun Koku Gijitsusho)
Z Mizuno Guraida Seisakusho

The first two letters and the series number remained the same for the service life of each design, however, minor to moderate changes in the design (usually reflected in a new Type Model number) were indicated by adding a second subtype number after the manufacturer's letter. Further minor changes were indicated by adding letters after the subtype number as in the Type/Model scheme above.

In a few cases, when the designed role of an aircraft changed, the new use was indicated by adding a dash and a second type letter to the end of the existing short designation. Thus the H6K4 was the sixth flying boat (H6) designed by Kawanishi (K), fourth version of that design (4). When the plane was equipped primarily as a troop or supply transport, its designation was then H6K4-L.

Popular Names

In July 1943, official names were given to JNAF aircraft in place of type numbers. These names were chosen based on the aircraft's primary role as listed below:

Popular Names
Fighters Meteorological phenomena
Carrier Fighters Wind names ending in pu or fu
Seaplane Fighters same as Carrier Fighters
Interceptor Fighters Lightning names ending in den
Night Fighters Light names ending in ko
Attack planes Mountain names
Bombers Star (sei) or constellation (zan) names
Patrol planes Sea or ocean names
Reconnaissance planes Cloud names
Trainers Tree, plant or flower names
Transports Sky names
Miscellaneous Named for landscape effects

These popular names were most used on designs which came into service later in the war, such as the Mitsubishi J2M Raiden (Thunderbolt) and Kawanishi N1K Shiden (Violet Lightning), both interceptors.

SADP Systems

The Service Airplane Development Program was begun in 1939 as a research program by the IJN's Bureau of Aeronautics. Each design studied was to be coded with its manufacturer's letter under the existing short designation system, plus a two digit number (i.e. 10, 20, 30, etc.). However this system was not widespread, and few records of SADP designations survived the war.

Japanese Army Aircraft Designations

The Japanese Army Air Force used two aircraft designation systems, the type number system and the Kitai number system. In addition, some types had a popular name.

Type Numbers

From 1927, new Army aircraft were given a type number based on the last digits of the Japanese year that the type was accepted into service. Up to the year 2599 (1939 in the West) the last two digits formed the type number. In 2600 (1940) the number 100 was used, and from 2601 (1941) only the last digit of the year was used.

Thus, the Army Type 97 Heavy Bomber and Army Type 97 Fighter were both accepted in 2597 (1937) and can be differentiated by the functional description attached to each.

New versions of an existing type were indicated by adding a Model number and letter, i.e. Army Type 3 Fighter Model 2A.

Kitai Numbers

The type number system required rather lengthy descriptive function names to fully identify an aircraft. The Kitai or Ki number system began in 1932 and assigned a number to each aircraft planned or projected to be built. Some existing aircraft also were given Ki numbers. At first the numbers were assigned sequentially but in 1944, new Ki numbers were scrambled, as if Allied intelligence wasn't confused enough!

New versions of an existing design had Roman numbers (I, II, III, etc.) added to the Ki number and subvariants had lower case letters (a, b, c, etc.) as used in some navy systems. And sometimes, the model and variant numbers and letters were supplanted by a Kaizo (KAI) or modification code! Let's look at the Kawasaki Hien, with a Kitai number of 61 and Allied code name TONY, as an example.

The project and prototypes were called Ki-61. The first two production versions were Ki-61-Ia and Ki-61-Ib. The next two versions carried KAI modification codes as Ki-61-I KAIc and KAId. Finally, the prototype of a second model was Ki-61-II and the first production of this new model was Ki-61-II KAIa. Whew!

Just to tie things up, the last example, the Ki-61-II KAIa was called the Army Type 3 Fighter Model 2A in the type number system. And a few foreign designed or built aircraft entered Japanese service, and these were given an alphabetical type rather than a numeric one, based on either the country of origin (Type I Heavy Bomber, for the Italian Fiat B.R. 20) or the manufacturer's name (Type LO Transport for the U.S. Lockheed Model 14).

Popular Names

Even the Japanese Army had problems using their lengthy aircraft designations in combat, and assigned popular names to many of the major combat types in service. Unlike the navy, however, the army chose names without any clear pattern.

Thus the Ki-61 fighter was Hien (Swallow), the Ki-43 fighter was Hayabusa (Peregrine Falcon) and the Ki-67 bomber was Hiryu (Flying Dragon).

The Allies Answer to Japanese Aircraft Designations

As you can imagine from the above discussion, even when one knows that the full designation of an aircraft is Aichi D3A1 Navy Type 99 Carrier Bomber Model 11, you might wish to have a short, simple and unmistakable name, especially when you are in combat with it!

In the second half of 1942, a colorful set of code names was developed in the Southwest Pacific Theater by the Air Technical Intelligence Unit (ATIU) of the Allied Air Forces in Australia. The head of the unit, Captain Frank T. McCoy Jr. was from Nashville, Tennessee, and the first few code names were hillbilly names such as ZEKE, NATE, PETE, JAKE and RUFE, as they were simple, short and distinctive. The basic system spread rapidly, and by late 1942, was adopted for use by both the USAAF and USN. In general, the code names were assigned using the following system, although several exceptions exist:

Basis of the Allied Code Names Scheme
Code Name Type Assigned to Aircraft Type
Male names Fighters (both Army and Navy, single or multi-engined)
and Reconnaissance seaplanes
Female names Bombers (including attack and dive-bombers),
Reconnaissance planes (land or carrier-based),
Flying boats and Transports (transport names began with "T")
Tree names Training aircraft
Bird names Gliders

Thus, the example Aichi given above, became simply VAL in the Pacific code name system. As we learned more about the various models of each type, the Japanese model number was often attached to the code name, as in ZEKE 32 for the A6M3 Type 0 Carrier Fighter Model 32 "Zero".

Obviously, these code names were much easier to remember and say for Allied airmen and thus, even today, discussions of the Pacific war are filled with names such as BETTY, PETE, OSCAR, KATE and TONY.

List of Japanese Army and Navy Aircraft and their Code Names

Aircraft marked with a single asterisk(*) were fictional, and did not exist. Those with a double asterisk(**) were identified as more than one type, i.e. they are duplicated in the list. This list is extracted and edited from Mikesh's Japanese Aircraft Code Names & Designations.

Japanese Army & Navy Aircraft and their Code Names
Service Type Number Desig. Manuf. & Model Code Name
Navy Type 90 Operations Trainer Mitsubishi K3M1 PINE
Navy Type 90-2 Flying-Boat Kawanishi H3K1 BELLE
Army Type 93-2 Twin-engine Light Bomber Mitsubishi Ki-2-II LOUISE
Navy Type 93 Intermediate Trainer Kugisho K5Y WILLOW
Navy Type 94 Reconnaissance Seaplane Kawanishi E7K ALF
Army Type 95-1 Intermediate Trainer Tachikawa Ki-9 SPRUCE
Army Type 95-3 Primary Trainer Tachikawa Ki-17 CEDAR
Army Type 95 Fighter Kawasaki Ki-10 PERRY
Navy Type 95 Reconnaissance Seaplane Nakajima E8N1 DAVE
Navy Type 96 Carrier Fighter Mitsubishi A5M CLAUDE
Navy Type 96 Carrier Fighter ** Mitsubishi (See CLAUDE) SANDY
Navy Type 96 Carrier Attack Bomber Kugisho B4Yl JEAN
Navy Type 96 Carrier Bomber Aichi D1A2 SUSIE
Navy Type 96 Reconnaissance Seaplane Aichi E10A1 HANK
Navy Type 96 Attack Bomber Mitsubishi G3M NELL
Navy Type 96 Transport Kugisho L3Y TINA
Navy Type 96 Reconnaissance Seaplane Watanabe E9W SLIM
Army Type 97 Command Reconnaissance Plane Mitsubishi Ki-15 BABS
Army Type 97 Heavy Bomber Mitsubishi Ki-21 SALLY
Army Type 97 Heavy Bomber ** Mitsubishi (See SALLY) JANE
Army Type 97 Fighter Nakajima Ki-27 NATE
Army Type 97 Fighter ** Nakajima (See NATE) CLINT
Army Type 97 Fighter * Mitsubishi ABDUL
Army Type 97 Medium Bomber * Kawasaki JULIA
Army Type 97 Light Bomber Mitsubishi Ki-30 ANN
Army Type 97 Transport Nakajima Ki-34 THORA
  Type 97 Light Bomber * Mitsubishi NORMA
Navy Type 97-1 and 97-3 Carrier Attack Bomber Nakajima B5N1 & 2 KATE
Navy Type 97-2 Carrier Attack Bomber Mitsubishi B5M1 MABEL
Navy Type 97 Flying Boat Kawanishi H6K MAVIS
Navy Type 97 Transport Nakajima L1N1 THORA
Navy Type 97 Seaplane Fighter * Nakajima ADAM
Navy Type 97 Reconnaissance Seaplane * Aichi BOB
Army Type 98 Light Bomber Kawasaki Ki-32 MARY
Army Type 98 Direct Co-operation Plane Tachikawa Ki-36 IDA
  Type 98 Medium Bomber * Heinkel He 111 BESS
  Type 98 Showa Light Bomber * Vultee V-11GB MILLIE
Navy Type 98 Reconnaissance Plane Mitsubishi C5M BABS
Navy Type 98 Reconnaissance Seaplane Aichi E11A1 LAURA
Navy Type 98 Bomber Float Plane * Aichi IONE
Army Type 99 Twin-engine Light Bomber Kawasaki Ki-48 LILY
Army Type 99 Assault Plane/Tactical Recon. Mitsubishi Ki-51 SONIA
Army Type 99 Advanced Trainer Tachikawa Ki-55 IDA
Navy Type 99 Carrier Bomber Aichi D3A VAL
Navy Type 99 S.E. Dive Bomber Seaplane ** Aichi (See JAKE) JUNE
Navy Type 99 Flying-Boat Kugisho H5Y CHERRY
Navy Type 99 Four-engine Flying Boat *   JOAN
Army Type 100 Command Reconnaissance Plane Mitsubishi Ki-46 DINAH
Army Type 100 Tactical Pilot Trainer Mitsubishi Ki-46-II KAI DINAH
Army Type 100 Interceptor Fighter Mitsubishi Ki-46-III KAI DINAH
Army Type 100 Heavy Bomber Donryu Nakajima Ki-49 HELEN
Army Type 100 Transport Mitsubishi Ki-57 TOPSY
Army Type 0 Medium Bomber ** Mitsubishi (See SALLY) GWEN
Army Type 0 Single-seat Twin-engine Fighter * Mitsubishi HARRY
Navy Type 0 Carrier Fighter Mitsubishi A6M ZEKE
Navy Type 0 Reconnaissance Seaplane Aichi E13A1 JAKE
Navy Type 0 Small Reconnaissance Seaplane Kugisho E14Y1 GLEN
Navy Type 0 Observation Seaplane Mitsubishi F1M1 PETE
Navy Type 0 Transport Douglas DC-3 L2D2/5 TABBY
Navy Type 0 Transport Mitsubishi L4M1 TOPSY
Army Type 1 Fighter Hayabusa Nakajima Ki-43 OSCAR
Army Type 1 Single-seat Fighter ** Kawasaki (See OSCAR) JIM
Army Type 1 Advanced Trainer Tachikawa Ki-54a HICKORY
Army Type 1 Operations Trainer Tachikawa Ki-54b HICKORY
Army Type 1 Transport Tachikawa Ki-54c HICKORY
Army Type 1 Freight Transport Kawasaki Ki-56 THALIA
Army Type 1 Transport Kokusai Ki-59 THERESA
Army Type 1 Light Bomber * Nakajima (See EVE) JOYCE
Navy Type 1 Attack Bomber Mitsubishi G4Ml/G4M6 BETTY
Navy Type 1 Formation Escort Fighter Mitsubishi G6M1 BETTY
Navy Type 1 Attack Bomber Trainer Mitsubishi G6Ml-K BETTY
Navy Type 1 Transport Mitsubishi G6M1-L2 BETTY
Navy Type 1 Target Plane Kugisho MXY4  
Navy Type 1 Dive Bomber * Nakajima (See JUDY) DOT
Navy Type 1 Single-seat Fighter ** Mitsubishi (See ZEKE) RAY
Army Type 2 Single-seat Fighter Shoki Nakajima Ki-44 TOJO
Army Type 2 Two-seat Fighter Toryu Kawasaki Ki-45 KAI NICK
Army Type 2 Advanced Trainer Manshu Ki-79  
Navy Type 2 Training Fighter Mitsubishi A5M4-K  
Navy Type 2 Fighter Seaplane Nakajima A6M2-N RUFE
Navy Type 2 Carrier Reconnaissance Plane Kugisho D4Yl-C JUDY
Navy Type 2 High-speed Recon. Seaplane Shiun Kawanishi El5Kl NORM
Navy Type 2 Flying-Boat Kawanishi H8K EMILY
Navy Type 2 Training Flying-Boat Aichi H9A1  
Navy Type 2 Land Based Reconnaissance Plane Nakajima J1N1-C IRVING
Navy Type 2 Gekko (Night Fighter) Nakajima J1N1-S IRVING
Navy Type 2 Primary Trainer Momiji Kyushu K9W1 CYPRESS
Navy Type 2 Intermediate Trainer Kyushu K10W1 OAK
Army Type 3 Fighter Hien Kawasaki Ki-61 TONY
Army Type 3 Command Liaison Plane Kokusai Ki-76 STELLA
Army Type 4 Heavy Bomber Hiryu Mitsubishi Ki-67 PEGGY
Army Type 4 Special Attack Plane Mitsubishi Ki-67-I KAl PEGGY
Army Type 4 Fighter Hayate Nakajima Ki-84 FRANK
Army Type 4 Primary Trainer Kokusai Ki-86 CYPRESS
Army Type 4 Assault Plane (See note) Kawasaki Ki-102b RANDY
Army Type 4 Special Transport Glider Kokusai Ku-8 GANDER
Army Type 4 Special Transport Glider** Kokusai Ku-8 (GANDER) GOOSE
Army Type 5 Fighter Kawasaki Ki-100  
Navy Type D Transport Douglas DC-3 TABBY
Navy Type He Interceptor Fighter Heinkel A7He1 (He 112B-0) JERRY
Army Type LO Transport Lockheed 14 THELMA
Army Type I Heavy Bomber Fiat B.R.20 RUTH
Navy Type S Two-seat Fighter Seversky A8V1 DICK

Sources and Further Reading

An excellent single source on Japanese Army and Navy aircraft is Rene J. Francillon's Japanese Aircraft of the Pacific War, published by Putnam and others.

Another specific reference is Japanese Aircraft Code Names & Designations by Robert C. Mikesh, published by Schiffer. This book has some interesting history behind the development of the Allied code names, as well as a short discussion of each aircraft, including some rather minor types.

For a humorous and unfortunately typical American view of Japanese military and naval air power in early 1941, check out the article Japan Is NOT an Air Power.

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All material not specifically credited is Copyright by Randy Wilson. All rights reserved.
E-mail to Randy Wilson: avhistory@rwebs.net