Common designation schemes
Type-designation
Most if not all Japanese military equipment since the Meiji restoration are designated by their adoption year. Depending on the period, they either go off the Calender, Japanese Calender, Or Emperor Period.
- Japanese Imperial Year: Starts with the founding of Japan in 660 BC.
- Japanese Era Name: Nengō (年号) Literally “year name” are names given to (usually) reign periods of Japanese Emperors.
- Shisaku number: After the shift of using Nengō years, the navy re-adopted the use of nengō for their prototype planes to distinguish commissioned prototypes from adopted models.
Year | Japanese Imperial Year | Nengō Era | Type Number | Shisaku Number |
---|---|---|---|---|
1868 ⋮ 1912 | 2528 ⋮ 2572 | Meiji 1 ⋮ Meiji 44 | Type 1 ⋮ Type 44 | |
1912 ⋮ 1926 | 2572 ⋮ 2586 | Taishō 1 ⋮ Taishō 15 | Type 1 ⋮ Type 15 | |
1927 ⋮ 1931 ⋮ 1945 | 2587 ⋮ 2591 ⋮ 2605 | Shōwa 2 ⋮ Shōwa 6 ⋮ Shōwa 20 | Type 87 ⋮ Type 91 ⋮ Type 5 | 6-Shi ⋮ 20-Shi |
1946 ⋮ 1989 | 2605 ⋮ 2649 | Shōwa | Type 46 ⋮ Type 89 | |
1990 ⋮ 2019 | 2650 ⋮ 2679 | Heisei | Type 90 ⋮ Type 19 | |
2019 ⋮ Present | 2679 ⋮ Present | Reiwa | Type 19 ⋮ Present |
Examples (Year — Designation Year):
- Type 11 37 mm infantry support gun (1922 — Taishō 11)
- Type 97 Medium Tank “Chi-Ha” (1937 — 2597)
- 12-Shi Carrier-Based Fighter (1937 — Shōwa 12)
- Type 74 MBT (1974)
Order and variants
A repeating pattern in Japanese vehicle designations (and outside of it in both civil and military use) are the Heavenly Stems and the Iroha.
Variants | Heavenly Stems
The Heavenly Stems is a system of ordinals originating in China and widely used across East Asia. During the Shang dynasty, it served as the names for the ten days of the week.
Within the Japanese militaries of WWII, this system was adopted for designating (typically minor) variations of various equipment, functioning similarly to the Western “Mark A/B/C” classification.
More extensively upgraded equipment is often designated with “Kai” (改) or “Kaizen” (改善) to signify large-scale improvements.
Heavenly Stems | Kanji | Romanji | Latin Equivelant | |
---|---|---|---|---|
1 | 甲 | コウ | Kō | a |
2 | 乙 | オツ | Otsu | b |
3 | 丙 | ヘイ | Hei | c |
4 | 丁 | テイ | Tei | d |
5 | 戊 | ボ | Bo | e |
6 | 己 | キ | Ki | f |
7 | 庚 | コウ | Kō | g |
8 | 辛 | シン | Shin | h |
9 | 壬 | ジン | Jin | i |
10 | 癸 | キ | Ki | j |
Improved | 改 (改善) | Kai (Kaizen) |
Examples:
- Ki-84 Kō / Otsu / Hei
- A6M5b Model 52 Otsu
- Type 4 Kō APHE (75 mm)
- Type 97 Chi-Ha Kai
- N1K2-Ja “Shiden Kai” Model 21 Kō
Order Sequence | Iroha
The Iroha is a famous Japanese poem known for being a perfect pangram, containing each character of the Japanese syllabary exactly once. Because of this, it was used as an ordering system for the syllabary, similar to how the Latin alphabet follows the sequence A, B, C, D…
The Imperial Japanese Army primarily used the Iroha system for tank designations (explained further below), along with occasional applications to other equipment. The Imperial Japanese Navy also employed it for submarine classification.
Order | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 |
Katakana | イ | ロ | ハ | ニ | ホ | ヘ | ト | チ | リ | ヌ | ル | オ |
Romanji | I | Ro | Ha | Ni | Ho | He | To | Chi | Ri | Nu | Ru | O |
Imperial Japanese Army
Aircraft (IJA)
The Imperial Japanese Army used two primary designation systems for its aircraft. The more widely known system in the Western world is the Kitai (Ki) index, which assigned a numerical designation to every Army aircraft project upon approval for development or commissioning by the Army High Command. This system functioned similarly to the Soviet “Object” designation for tanks.
Aircraft that were officially adopted into service received a full Type designation, as was common for Japanese military equipment. These designations typically followed the standard format “Type XX [Role]”, with small variants identified with the Heavenly stems and larger remodels separated by Model.
Ki — Kitai: Airframe number/index
- Ki-10 — Type 95 Fighter
- Ki-43-II — Type 1 Model 2 Fighter
- Ki-102b — Type 4 Otsu Assault Aircraft
Ki-43 — Hayabusa (隼, Peregrine falcon)
- The Ki-43 was the newest fighter and first Japanese Army aircraft to receive a nickname.
- The name “Hayabusa” is said to have been taken from the opening phrase of the 64th Sentai’s unit song.
- Shortly after the start of the Pacific War, “The New Land Eagle, Hayabusa, Appears” made headlines in newspapers.
- Shōki was a Taoist deity in Chinese mythology, traditionally regarded as a vanquisher of ghosts and evil beings.
- The nickname was chosen to the Shōki Shrine in Higashiyama Ward, Kyoto, where the first deployment took place.
Ki-45 — Toryū (屠龍, Dragonslayer)
- The term first appeared in newspaper articles reporting on the exploits of the 4th Sentai and other flying units equipped with the Ki-45, which played an active role in shooting down B-29 bombers during the air defense of the Japanese mainland.
- The term portrayed the B-29 as the dragon, and the Ki-45 its slayer.
- It is named after Daikoin Temple and Donryū in Ota City, Gunma Prefecture, where the Nakajima Aircraft Ota Factory was located.
Ki-61 — Hien (飛燕, Flying Swallow)
- The name was chosen due to the sleek silhouette of the aircraft, which was achieved by using a large aspect wing ratio and a liquid-cooled engine.
- It was popularized from January 1945 onwards, where it began to appear in newspaper articles reporting on the Japanese mainland air defense squadrons, led by the 244th Sentai, which were equipped with Ki-61s.
Ki-67 — Hiryū (飛龍, Flying Dragon)
Ki-84 — Hayate (疾風, Gale)
- The nickname itself was chosen by the Ministry of the Army after a public vote.
- The plane was announced in various newspapers on April 11, 1945 with photos, along with the quote: “It is a fitting name to praise the heroic figure of our fighter planes as they pounce on the enemy like a gale.”
Ki-200 — Shusui (秋水, Sharp Sword)
Tanks (IJA)
The first three adopted Japanese tanks were designated only by order of the Iroha without a role, while other tanks were subdivided by role and order with Iroha:
- Type 89 I-Go — 1st model of the Imperial Japanese year 2589 (1929)
- Type 95 Ro-Go — 2nd model of the Imperial Japanese year 2595 (1935)
- Type 95 Ha-Go — 3rd model of the Imperial Japanese year 2595 (1935)
² Tanks after the Ha-Go were subdivided by vehicle class and the previous 3 were retroactively counted into the new designation system (BUT never actually designated as such)
Romanji | Katakana | Kanji | Literal Translation | Role |
---|---|---|---|---|
Ke | ケ | 軽 (Kei) | Light | Light Tank |
Chi | チ | 中 (Chū) | Medium | Medium tank |
O | オ | 大 (Ō) | Large | Heavy Tank |
Ho | ホ | 砲 (Hō) | Gun | SPG |
Ka* | カ | 海 (Kai) | Sea | Amphibious Tank (IJN) |
Example:
- Type 2 Ka-Mi
- Type 3 Ka-Chi
- Type 4 Ka-Tsu
- Type 5 To-Ku
- Type 98 Ta-Se (Taikū Sensha)
- Type 98 So-Ki
- Type 5 Na-To
Imperial Japanese Navy
Aircraft (IJN)
In the late 1920s, the Navy adopted a short designation naming scheme to indicate the role and manufacturer of the plane next to their standard type designation.
- Standard Type Designation: Type 90 Carrier Fighter
- New Short Designation: A2N (Carrier Fighter — 2nd Type — Nakajima)
After 1929, the long designation got additional information with model designation to indicate variant information, the first number for fuselage/wing changes, the second number for engine, and an optional third letter to signify armament changes
First letters (role)
Letter | Japanese | Role | Example |
---|---|---|---|
A | 艦上戦闘機 | Carrier-based fighter plane | A6M |
B | 艦上攻撃機 | Carrier-based attack bomber | B6N |
C | 艦上偵察機 | Carrier-based reconnaissance plane | C6N |
D | 艦上爆撃機 | Carrier-based dive bomber | D4Y |
E | 水上偵察機 | Ship-based reconnaissance hydroplane | E13A |
F | 水上観測機 | Ship-based observation hydroplane | F1M |
G | 陸上攻撃機 | Land-based attack bomber | G4M |
H | 飛行艇 | Flying boat | H8K |
J | 陸上戦闘機 | Land-based fighter plane | J2M |
K | 練習機 | Trainer | K10W |
L | 輸送機 | Transport | L2D |
M | 特殊機 | Special purpose | M6A |
N | 水上戦闘機 | Fighter hydroplane | N1K |
P | 陸上爆撃機 | Land-based bomber | P1Y |
Q | 哨戒機 | Patrol plane | Q1W |
R | 陸上偵察機 | Land-based reconnaissance plane | R2Y |
S | 夜間戦闘機 | Night fighter | S1A |
X* | 実験 | Experiment (Special Purpose) | JXFw (Fw 190) |
Notes:
- X was only used to replace the first number and never used separately. It was mostly used as special-purpose test beds (MX) and as tech demonstrator imported vehicles filling their respective roles (JX, AX, etc.).
- All (But X) can be added to an already existing plane as a suffix to indicate a role refit (N1K-J, A6M-N)
Second letters (manufacturers/designers)
Letter | Japanese Manucturer | Foreign Manufacturer | Foreign Example |
---|---|---|---|
A | Aichi | North American | KXA (NA-16) |
B | Boeing | AXB (P-12 / F4B) | |
Bu | Bücker | KXBu (Bü 131) | |
C | Consolidated | HXC (P2Y) | |
D | Showa | Douglas Dewoitine Northrop | LXD (DC-4E) AXD (D.500) DXD (Northrop BT) |
F | Fairchild | LXF (Fairchild 91) | |
Fw | Focke-Wulf | JXFw (Fw 190) | |
G | Hitachi | Grumman | AXG (Grumman F) |
H | Hiro | Hawker | AXH (Nimrod) |
He | Heinkel | AXHe (He 100) A7He (He 112) | |
J | Nihon | Junkers | LXJ (Ju 86) |
K | Kawanishi | Kinner | LXK (Kinner Envoy) |
M | Mitsubishi | Airspeed | LXM (Airspeed Envoy) |
N | Nakajima | ||
P | Nihon | ||
S | Sasebo | ||
Si | Showa | ||
V | Vought | AXV (V-141) | |
W | Wanatabe (Kyushu) | ||
Y | Yokosuka | ||
Z | Mizuno |
Official name designation
After July 1943, adopted planes got a name and variant number instead of a full type and model designation.
(ex. [N1K1] “Kyōfū 11” vs [A6M2] “Type 0 Carrier Fighter Model 21”)
Fighters: Weather and meteorological names
Naval Fighters: Wind (「風」appended as “pū” or “fū”)
- A7M Reppū (烈風, Strong* Wind)
- N1K Kyōfū (強風, Strong Wind)
- J6K Jinpū (陣風, Squall)
Interceptors: Electric/Lightning (「電」”den”) and Thunder (「雷」“rai”)
- J2M Raiden (雷電, Lightning Bolt)
- J5N Tenrai (天雷, Heavenly Thunder)
- J7W Shinden (震電, Magnificent Lightning)
- N1K Shiden (紫電, Violet Lightning)
Night Fighters: Light (「光」appended as “kō”)
- J1N-S Gekkō (月光, Moonlight) (not in-game variant)
- P1Y-S Kyokkō (極光, Aurora) (not in-game variant)
“Attack” Bombers: Mountain (「山」appended as “zan”)
- B6N Tenzan (天山, Heavenly Mountain)
- G5N Shinzan (深山, Deep Mountain)
- G8N Renzan (連山, Mountain Range)
“Dive” Bombers: Stars/Constellation (「星」“sei”)
- D4Y Suisei (彗星, Comet)
- B7A Ryūsei (流星, Shooting Star)
- P1Y Ginga (銀河, Galaxy)
Patrol: Sea/ocean (「海」“kai” /「洋」“yō‘)
- Q2M Taiyō (大洋, Great Sea) (not in-game variant (Ki-67))
Reconnaissance: Cloud (「雲」appended as “un”)
- R2Y Keiun (景雲, Cirrus Cloud)
Transports: Sky (「空」appended as ”ku”)
Trainers: Plants
Miscellaneous: Landscape
- J8M1 Shūsui (秋水, Autumn Water / Sharp Sword)
(not in-game variant)
“Special Attack” aircraft: Flower (「花」appended as “ka”)
- Kikka (橘花, Orange Blossom)
Vessels (IJN)
* Ships usually maintain their original name as laid down if a ship-type reclassification/remodel happens.
Only playable in-game vehicles are listed (unless relevant and specified)
- Carriers — names related to flying animals, actual or mythological
- Shōkaku (翔鶴, Soaring Crane)
- Battleship — provinces, or alternate names of Japan
Kawachi-class (BB)
- Settsu (摂津, Settsu Province)
Fusō-class (BB)
Ise-class (BB → BBV)
Nagato-class (BB)
- Mutsu (陸奥, Mutsu Province)
- Battlecruisers and heavy cruisers — mountains
Tsukuba-class (CA)
- Ikoma (生駒, Mount Ikoma)
Ibuki-class (CA)
- Kurama (鞍馬, Mount Kurama)
Kongō-class (BC → *FBB)
Amagi-class (BC → *CV)
- Amagi (天城, Mount Amagi)
- Akagi (赤城, Mount Akagi)*
Aoba-class (CA)
- Aoba (青葉, Mount Aoba)
Myōkō-class (CA)
Furutaka-class (CA)
- Light cruisers — river names
Kuma-class (CL)
- Kuma (球磨, River Kuma)
- Tama (多摩, River Tama)
Izuzu-class (CL)
- Isuzu (五十鈴, River Isuzu)
Sendai-class (CL)
- Sendai (川内, River Sendai)
Yūbari (CL)
- Yūbari (夕張, River Yūbari)
Agano-class (CL)
- Agano (阿賀野, River Agano)
Mogami-class (CL → *CA)
Tone-class (CL → *CA)
- Tone (利根, River Tone)
- Training cruisers — Shinto shrines
- Destroyers — weather, wind, tide, current, wave, moon, season, other natural phenomena, plants
- Momi (樅, White fir)
- Mutsuki (睦月, January)
- Satsuki (皐月, May)
- Ayanami (綾波, Twilled Waves)
- Hatsuharu (初春, Early Spring)
- Nenohi (子日, New Year Day)
- Yūdachi (夕立, Evening Squall)
- Yūgumo (夕雲, Evening Clouds)
- Hayanami (早波, Early Waves)
- Kiyoshimo (清霜, Clear Frost)
- Shimakaze (島風, Island Wind)
- Akizuki (秋月, Autumn Moon)
- Hatsuzuki (初月, New Moon)
- Matsu (松, Pine Tree)
- Torpedo boats — birds
Chidori-class
- Chidori (千鳥, Plover)
- Gunboats — places of scenic beauty and historic interest
- Coast defence ship/Escort ships — islands
Hiburi-class
- Shōnan (昭南, Singapore Island)
- Submarines — number sequence starting off the Iroha
1st-Class: I-1 — … (> 1,000 t Displacement)
- *I-19 → I ku
- *I-400 → Shi on
2nd-Class: Ro-1 — … (1,000 — 500 t Displacement)
3rd-Class: Ha-1 — … (< 500 t Displacement)
*Additionally, submarines were often given nicknames, derived from alternative readings of their numerical designations in Japanese.
- Submarine tenders — whales
- Seaplane tenders — abstract noun, idiomatic word, notable achievement vessels in past war(s)
Gun Manufacturer/Designer
The designation of most naval artillery cannons in the IJN was not solely based on the year of adoption, as is common within Japanese conventions. Instead, it was determined by the adoption year of the breech design. This means that even if a gun was introduced or produced later, its designation would still reflect the year in which the breech mechanism was first standardized.
Initially imported or license-built weapons were designated by the manufacturer, but would later be simplified under the standardized Japanese Navy convention
ホ — HO: Hotchkiss (FR)
- 13.2 mm/99 "HO" Type → Type 93 13.2 HMG
ヒ/ビ — HI / BI: Vickers (UK)
- 7.7 mm/94 (0.303") "HI" Type
- 12 mm/62 (0.50") "HI" Type → Type 12 Single-barreled MG
- 40 mm/62 (1.575”) “HI” Type → Type 91 40 mm AA
ル — RU: Lewis (UK)
- 7.7 mm/87 (0.303") "RU" Type → Type 92 7.7 mm LMG
カ — KA: Canet (FR)
- 12.6"/38 (32 cm) “KA” Type → 32 cm Type 41
アン — AN: Armstrong (UK)
- 12"/45 (30.5 cm) “AN” Type → 30 cm Type 41
- 12"/50 (30.5 cm) “AN” Type → 30 cm Type 41
コク — KOKU: Krupp (DE)
Japanese Self-Defense Forces (JSDF)
Aircraft (JASDF)
The naming conventions for JSDF aircraft were originally established on April 16, 1974, under directive 防装航第1725号. After multiple revisions, the current regulations are outlined in 防装庁(事)第31号, issued on June 3, 2019.
The system is primarily based on the U.S. military aircraft designation system (MDS), meaning that the structure of letters and numbers used in JSDF aircraft designations follows a similar pattern to the U.S. system.
- (1) Technical development status
- (2) Changed Mission Designation
- (3) Basic Mission Designation
- (3+) Particular Aircraft Type
- (4) Design or Adoption Number
- (5) Design change designation
- (5+) Additional design change
(2|3) Mission Role:
(3+) Particular Aircraft Type
- H: Helicopter (ヘリコプター)
- S: Seaplane (飛行艇)
- V: VTOL (ティルトローター機)
- G: Glider (グライダー)
Tanks (JGSDF)
Prototype designations
From two years after the start of the JSDF (1956) until the 1980s, the JGSDF used 2 letter code prototype codes starting at SS and going further alphabetically:
- SS — Experimental Tracked Armored Vehicle → Type 60 SPRG
- ST(A) – Experimental Medium “Special Vehicle” → Type 61 MBT
- ST(B) → Type 74 MBT
- ST(C)* → Type 90 MBT*
- SU — Experimental Armored Transport → Type 60 APC
- SU(B) → Type 73 APC
- SV – Experimental Self-Propelled Mortar → Type 60 SPM (81 mm)
- SW – Experimental Mine-Disposal Vehicle
- SX – Experimental Self-Propelled Howitzer → Type 60 SPM (107 mm)
- SY – Experimental Self-Propelled Gun → Type 56 SPH (105 mm)
- SZ – Experimental Special Transport Vehicle
* While widely known as the development designation of the Type 90 MBT, the development started after the abandonment of this designation system around the 1980s. The correct designation system would fall under “TKX”, particularly:
“TKX-1-[Chassis Number]” — Type 90 MBT
“TKX-2-[Chassis Number]” – Type 10 MBT (TKX-2-0005)
Vessels (JMSDF)
Unlike the IJN, ship names are in Hiragana instead of Kanji
- Helicopter destroyers and Helicopter carriers (DDH) — traditional provinces and mountains
- Guided missile destroyers (DDG) — mountains and weather terms
- Small destroyers (DD) — weather terms
- JDS Harukaze (DD-101) (はるかぜ, Spring Wind)
- JDS Ayanami (DD-103) (あやなみ, Twilled Waves)
- JDS Murasame (DD-107) (むらさめ, Passing Shower)
- JDS Yūgure (DD-184) (ゆうぐれ, Twilight)
- Frigates (DE) — rivers (*initially weather terms)
- JDS Akebono (DE-201) (あけぼの, Daybreak)*
- JDS Ikazuchi (DE-202) (いかづち, Thunder)*
- JDS Isuzu (DE-211) (いすず, Isuzu River)
- JDS Chikugo (DE-215) (ちくご, Chikugo River)
- Submarines (SS) — ocean currents and legendary auspicious animals
- Replenishment oilers (AOE) — lakes
- Amphibious transport docks and Troopships (LST) — peninsulas