Now Comes Theodora

Japanese aircraft code-names in perspective

Richard L. Dunn © 2005

The aircraft code-name FAGOT may not ring a bell. It is the code-name of one of the most famous fighters in the world. It is not a code-name for a Japanese aircraft but is part of an elaborate system of code-names adopted by NATO early in the Cold War to identify Soviet aircraft. FAGOT is the code-name for the MiG-15. The MiG-15 designation is well known even by many people who are not aviation buffs. The name FAGOT is known by far fewer people and not regularly used even by those who know it! Why is this? My guess is that it doesn't make much sense to use a code-name when the official name is known and easy to use.

The FAGOT example suggests a question, why do World War Two aviation buffs, including many serious historians, persist in using code-names for aircraft whose actual designations are well known? Please note: I am not now referring to quoting or paraphrasing a combat report or contemporaneous document that uses the term. That is entirely legitimate. Rather, why are code-names in general use in preference to well-known official designations or terminology actually used by those who flew or built the aircraft? We don't do this for the MiG-15 or the FW-190 (S.W.P.A. code-name FRED) but we do it for OSCAR and VAL and BETTY. Sometimes ZEKE is used for Zero but this seems less frequent.

This essay will not attempt to answer the question posed in the previous paragraph. Instead, it will review the origins of code-names and suggest some of the fallacies or inaccuracies involved in their general use.

The NATO code-name system was apparently adopted in part because the Soviet Union's closed totalitarian system kept many new aircraft designations shrouded in secrecy. Codenames were used to identify aircraft systematically before their official designations became known. This seems a perfectly legitimate use of aircraft code-names. In order to make a comprehensive system code-names were awarded even to some earlier aircraft with known designations. After the aircraft's official designation becomes firmly established you would expect the code-name to fall into disuse. This happened in the case of many Soviet aircraft that remained in use long after their official designation became known. For example, FAGOT fell into disuse while BEAR, so evocative of the big Tu-95 and a symbol of Russian might, retained substantial currency. This suggests one of the lines of inquiry to be investigated. Were Japanese aircraft code-names adopted because their official designations were unknown? Did they continue in use because they were somehow more useful than official designations?


Many Japanese aircraft and their official designations used in the opening months of the Pacific War were already known to Allied intelligence services prior to the war. Most of the Japanese aircraft had been fairly well described and often illustrated in aircraft recognition manuals. It is, however, clear that the most up to date manuals had received less than universal distribution or had not been carefully studied since many reports written early in the war use descriptive terms rather than designations to identify enemy aircraft encountered.

Some aircraft such as the Mitsubishi Type Zero Carrier-based fighter (REI-SHIKI KANJO SENTOKI) rapidly became well known and were identified by various terms including "Zero", "Navy Zero", or "Navy Nought." On the other hand, the Japanese army's Type 1 fighter which had not seen combat over China prior to the Pacific War was unknown to Allied intelligence at the beginning of the war. When encountered in combat it too was often identified as a Zero.

The Japanese navy's Type 96 Land-attack bomber (KYU-ROKU SHIKI RIKUJO KOGEKIKI) was relatively well known, as was the army's Type 97 Heavy bomber (heavy bomber - JUBAKUGEKIKI). The navy's newer Type 1 Land-attack bomber was more illusive and was usually identified as one of the other two. Eventually it was recognized as a separate type and a variety of descriptive terms ("Wellington type" or "pointed nose" bomber) were applied to it.

The pattern in the early months of the war followed by the Americans, British Commonwealth, Chinese and Dutch forces was to apply official designations when known and use descriptive terms when no designation was known. Identifications like "four-engine flying boat similar to Sikorsky S-42" were used.

An attempt was made to standardize aircraft identifications by assigning serial numbers to aircraft. Serial numbers applied whether the official designation was known or unknown. The serial was generally used in conjunction with an official designation when known and in conjunction with a descriptive term if the official designation was unknown. This system was adopted in the Southwest Pacific Area but was never fully implemented. The Zero fighter being well known was almost never referred to by its serial number "Serial 48." This system was widely used in the S.W.P.A. among intelligence officers and in official reports but never seems to have fully displaced commonly known official designations among many aircrew members.

The serial number system apparently gained no hold in the China-Burma-India Theater or with the U.S. Navy outside the S.W.P.A. In those theaters the mix of official designations and descriptive terminology continued. "Official designations" used by the Allies were not always entirely correct. The Japanese navy terminology "Land-attack bomber" in intercepted radio messages was initially mistranslated as "army bomber" by the Allies. This resulted in some confusion. The existence of the navy's Zero and the army's Type 1 fighter gave rise to the notion that there were two types of Zeros. Conveniently two designations for the Zero gained currency, the "Mitsubishi Zero" and the "Nagoya Zero." U.S. Navy pilots seemed to encounter more "Nagoya Zeros" than "Mitsubishi Zeros." This "confusion" seems not to have interfered with the combat performance of U.S. Navy fighters.

As months of the war passed the Allies gradually gathered more intelligence and were better able to accurately identify Japanese aircraft. Data plates from aircraft fuselages and other components were recovered, prisoners were taken, and documents captured. Conflicting data was checked. Recognition manuals were revised. By the second half of 1942 most of the aircraft in frequent use by the Japanese in the early months of the war had been identified by the Allies. At this point it was possible to apply reasonably accurate official designations to most aircraft likely to be encountered.

A Vision So Noble

The Allies used shorthand versions of known designations almost from the beginning. The prime example is the simple "Zero" for "Type Zero Carrier-based fighter." In written notation "T. 97 H.B." often replaced "Type 97 Heavy bomber."

If, as indicated above, the Allies had a fairly good handle on Japanese official aircraft designations, why introduce a code-name system? The reason is certainly not entirely clear but the examples in the preceding paragraph may suggest what was thought to be a potential problem. Aside from the Mitsubishi/Nagoya Zero canard it was discovered that the Zero fighter was not the only "Type Zero." The Japanese had several Type Zeros (some misidentified as such by the Allies) including two different floatplanes and a transport aircraft. The Type 97 "heavy bomber" was a medium bomber by Allied standards and was often referred to as such.

The Allies did not have a uniform system of identifying Japanese aircraft during most of 1942. There was a common feature that evolved and was used in the various systems, however. That is, when the official Japanese designation was known, it, or a shorthand version of it, was used or made part of the designation adopted. The system was flexible and accommodated unknown aircraft including newly fielded types by utilizing descriptive terms to identify them. For example: the Mark Two version of the Zero fighter (later designated model 32) was identified by the Allies as a "square wing Zero" or "Mark II Zero."

It may not be entirely possible to explain the adoption of a system of code-names for Japanese aircraft designations when a seemingly workable system was in place and gradually evolving. The story of how the code-name system was adopted may be of interest to students of organizational behavior or historians interested in the style and personality of Lt. Gen. George C. Kenney, however.


In July 1942 Maj. Gen. George Churchill Kenney left his post as commander of the 4th Air Force in the western United States and headed for the Southwest Pacific where he would take over as commander of the U.S. 5th Air Force and also the Allied Air Forces in the S.W.P.A. The southwest Pacific was then the most active combat area in the Pacific. After a whirlwind inspection tour Kenney took over his new post on August 4th. His new command needed a shake up. Kenney perceived there was too much dead wood and too few "operators" in his organization to get done the things he considered necessary. Kenney made it clear to his staff that it was results not bureaucratic niceties that he sought.

Much good work had been going on under Kenney's predecessor Lt. Gen. George Brett. The intelligence staff at Allied air-headquarters (Australians as well as Americans) had been collecting information and photographs of Japanese aircraft, armament and air organization. They proposed a comprehensive manual on the subject. Noting the lack of uniformity in Japanese aircraft designations, a system of code-names was suggested for inclusion in the document. Frank T. McCoy of Kenney's intelligence staff selected most of the names and many betrayed his background and penchant for names common or unique to the Ozarks or other parts of the southern United States.

In September 1942 "Intelligence Information Memorandum No. 12, Japanese Air Services and Japanese Aircraft" was published. It was an impressive and professionally printed document. Laced between its durable covers were glossy pages that contained clear print and high-resolution lithographs of near photographic quality. The information it contained was state of the art (it is informative even today).

Right at the beginning of the document was an introduction explaining the need for a system of code-names. It used the example of the possible confusion caused by multiple "Zeros." The Zero was awarded the code-name ZEKE. Each section describing an aircraft was headed by its newly created code-name (with its official designation in smaller print). The second page of the memorandum was titled "JAPANESE AIRCRAFT" with a "LIST OF IDENTIFYING NAMES (Replacing Serial Numbers)." This list awarded code-names to Japanese aircraft that had never been encountered in the S.W.P.A. The first two pages of the memorandum were virtually a sales tool for the code-name system.

McCoy appears to have been an "operator", the kind of staff officer Kenney liked. The intelligence memorandum was a valuable document well worth sharing. Shared it was! It was not only sent in quantity to army, navy and air units in the S.W.P.A. but to London, Washington, Hawaii, New Zealand, and numerous outpost islands in the Pacific. Kenney probably considered it a minor point that neither he nor McCoy had any authority to do this. Having forgotten Chennault in China, one hundred copies were sent there by urgent air transportation on October 16th.

With the memorandum widely distributed, McCoy drafted for Kenney's signature cable messages to air headquarters in Washington and London recommending adoption of the list of aircraft designations. A week later a separate message was prepared for China as well. Possibly as prelude to requesting the Supreme Commander's (MacArthur) intervention in the matter, this message was routed to General Headquarters for coordination and approval.

Flying Tigers

This message made the case for adopting the code-names. "Many publications from London and Washington name leading Japanese fighter as 'Mitsubishi Zero' and 'Nagoya Zero.' Much confusion in this case of using Nagoya as manufacturer when fact exists only geographical location of one Mitsubishi factory. Some aircraft also made by Nakajima. Have urged Washington, Hawaii, and London accept list of proper names, types and identifying code-names all Jap aircraft published by this headquarters as standard_"

Kenney's message was referred to General Headquarters on November 4th and had not yet been acted upon when a reply to his earlier message came from the British Air Ministry. "Your signal 27/10 explaining suggested use code names for Japanese aircraft appreciated. Operational requirements necessitate abbreviations, but consider essential that official style of designations be adhered to except for purely local purposes. These designations will be given in Japanese section of AP 1976_Revision following receipt of captured documents identifying aircraft as follows. Navy or Army, followed by type number, followed by duty. Example Navy 00 (R); 00 Deck Landing Single Seat Fighter. When known we are including the manufacturer's name."

At General Headquarters Maj. Gen. Stephen J. Chamberlain sent a note to Maj. Gen. Richard K. Sutherland, MacArthur's Chief of Staff. The note reviewed the previous correspondence and stated: "2. It appears that the Air Force has established a list of identifying names (replacing serial numbers) for Japanese aircraft_The radiogram proposes that the list_be accepted as universal. 3. Unless the correspondence outside the Southwest Pacific Theater has been approved by you, the Air Force erred in sending all this data...._G-3 believes it to be another case of using improper channels. 4. I doubt we should attempt to impose our own system upon others.... 5. G-3 opinion is that it would be much better to refer to Japanese aircraft by types rather than some identifying name. Code names can be very much overdone_....G-3 recommendation is that this radiogram not be sent and that the Air Force reconsider their former action of utilizing identifying names. Suggest that this matter be taken up with General Kenney."

On the 11th of November Sutherland signed a buck slip saying the radiogram should be withdrawn. There is no indication he spoke to Kenney about the matter. Kenney's star was on the rise at this point and Sutherland, consummate politician that he was, probably saw no need to confront Kenney or push the matter further.

Intelligence memorandum No. 12, with the argument for a list of aircraft names right in the front, had already been spread throughout the Pacific. Many intelligence officers probably thought they had received it because it had official endorsement. It seems unlikely that the twin terms "Mitsubishi" and "Nagoya" Zero could cause any serious confusion. But when the truth of the assertion that these were redundant terms became widely known it could only add credibility to the S.W.P.A. claims that code-names were needed.

Codenames largely based on the original S.W.P.A. list later were officially adopted but that was almost acceptance of a fait accompli. Rather than reasoned discourse, force of personality and bending the rules were the primary factors in acceptance of the code-names.


There was some delay before the new code-names began to take hold in the S.W.P.A. The most commonly encountered enemy aircraft was the Zero fighter and the sobriquet Zero died hard. While the new code-names were official policy in the 5th Air Force at least by October 1st, the first combat victory using the new terminology may have been a VAL claimed early in December 1942. Soon thereafter ZEKE appeared in a combat report but the term Zero continued in common usage for many months. When the Type 1 fighter was first encountered that same month both Type 1 and OSCAR appear in combat reports but soon OSCAR began to predominate. Among intelligence summaries issued from headquarters parallel designations using both the code-name and Japanese type designation (usually abbreviated) prevailed through 1943 and later.

Navy carrier pilots and Marine fighter pilots on Guadalcanal continued to distinguish between Nagoya and Mitsubishi Zeros until late in 1942. They reported both types during the Battle of Santa Cruz in late October 1942. "Nagoya Zeros" were reportedly encountered over Munda late in December 1942 but code-names had already begun to creep into combat reports and intelligence summaries from the Solomons. RUFE and PETE had been mentioned in November 1942. Early in 1943 ZEKE and HAMP appeared with some frequency and gradually displaced the earlier terminology.

As far as the Tenth Air Force in the China-Burma-India Theater is concerned the change (at least in official intelligence summaries) came early in 1943. Fighter pilots do not always speak in terms of intelligence summaries. "Zero" long remained in the parlance of fighter pilots including malapropisms such as "OSCAR type Zero." Robert Scott, commander of the 23rd Fighter Group, left China in early 1943. Soon after returning to the United States he published God Is My Co-Pilot. Not a single Japanese aircraft is identified by a code-name in Scott's book.

As aircrew and intelligence officers familiar with the old designations were replaced by new men without the baggage of the old knowledge the code-names were accepted ever more widely. During the last year of the war the code-names had achieved almost universal acceptance among operational aircrews. Even the British in India and Burma accepted the code-names.

Tales of the Flying Tigers


In the discussion above it has been suggested that there really was no strong imperative to adopt a code-name system. Kenney and McCoy associated their list with an impressive looking and useful document. They circulated it widely in an unauthorized manner. Only after this did they press through official channels to have the list accepted. Had the idea of a code-name system been totally without merit even such a preemptory strategy would not have worked. The strategy worked and the system eventually was accepted. Even after acceptance the use of official designations in lieu of or in addition to code-names prevailed for a substantial period and never completely died out.

The code-name system eventually became the dominant system for identifying Japanese aircraft during the war. Arguably it has merits over an abbreviated official system. It allows an observer to identify an aircraft for reporting purposes without knowing its official designation or even its mission type. If that is a strength it seems that it could also be a weakness. Is it inherently better or easier to remember a name (that may have other connotations) than number and type? The system was not primarily used to designate new aircraft whose official designation was unknown. In fact it sometimes probably hurt rather than helped. Before the Type 2 Carrier-reconnaissance plane was identified and designated JUDY it was often identified as a TONY in combat reports. If the pilot in a carrier action had thought "army type 3" before reporting his sighting perhaps he would have realized the incongruity of his observation. Likewise DINAHs (female gender indicative of a bomber) were often inaccurately reported as engaging in bombing raids. Other similar examples could be cited. This flaw may not be unique to the code-name system but that system did nothing to improve aircraft identification.

Presumably the code-name system was thought to have utility at the time. One of the "faults" of using official designations as illustrated by the Air Ministry cable quoted above is that they evolve. The Air Ministry proposed to add data to official designations (such as manufacturer's name), as it became known. The code-name system was, however, not exempt from evolution. For example HAP changed to HAMP, then ZEKE 32. The simple ZEKE multiplied into ZEKE 21, 22, and 52 in addition to the ZEKE 32. Is this really simpler or better than Zero 21 and so forth? In other cases the Japanese aircraft evolved, sometimes with fairly significant changes in appearance, but the designation did not keep pace with the change. The code-name system was neither better nor worse than its predecessor in this regard.

It appears adoption of a code-name system compared to an abbreviated official type designation system constituted a marginal gain in utility if any. As recounted above adoption of the system did not depend on its increased usefulness but on other factors. The code-name system was not primarily created to deal with unidentified aircraft types. In short, there was no strong reason to adopt the system.

The code-name system is a historical fact. Historians can hardly ignore it. That does not mean that it makes sense today to use the code-name system as the general or dominant system for referring to Japanese aircraft in the Pacific War. General use of the system ignores the fact that the Japanese did not use it at all. It was not used at all by the Allies for tactical purposes for nearly the entire first year of the war. The system rapidly gained acceptance during 1943 but not necessarily to the exclusion of earlier systems. Only during the late phases of the Pacific War did the system predominate and then gain a near monopoly of use.

We don't refer to the Bf-110 as DOC, the Ju-87 as IRENE, or the Ju-88 as JANICE. They received those designations in intelligence memorandum No. 12. Incidentally, FRANK was the name originally awarded to the "T.K. 4, 2E, SSF" whatever that is. Frank McCoy awarded the designation GWEN to the non-existent Mitsubishi Type Zero medium bomber! The people that created the original list of Japanese aircraft designations only knew what they knew and they didn't always get it right. Why do many people slavishly following a practice that began under such questionable circumstances?

One final point in this discussion is that not once has a Japanese army kitai designation been mentioned nor has a navy "model-type" designation (such as A6M2) been mentioned. The reason for this is that historically these designations played virtually no part in the discussion of the issue because they were generally unknown to the Allies until late in the war. They were unknown because the Japanese seldom used them in front-line operations. Despite volumes of captured documents, prisoner of war interrogations, intercepted messages and captured data-plates there was little evidence such designations constituted a system in general operational use by the Japanese (as distinguished from specialized use for some production and logistics purposes). Some of the seemingly authentic designations used in publications today (for example, Ki 43-Ic) simply cannot be found in historic records. They are undoubtedly post-war creations. In other cases the designations existed, they simply weren't in such general use as common practice today indicates.


A complete description of Japanese aircraft designations is beyond the scope of this article. The Japanese in fact had multiple systems. The long form with Japanese calendar year was the most common and used by both the Japanese army and the navy but with slight variations. Year 2600 (1940) was Zero in navy nomenclature but 100 in army terminology. Other examples of differences were noted above ("land-attack" versus "heavy bomber"). Designations were sometimes awarded on a temporary basis. When the official designation became final, slight changes were sometimes made. The navy adopted a two-digit model system in late 1942 (Zero carrier fighter Mark 1 eventually became Zero models 11 and 21).

Other systems included the navy model-type and army kitai systems (examples, A6M2 and Ki 43) already mentioned. Additional systems (navy OBA and army Kana [e.g., "Se" equates to Sentoki or fighter]) were used primarily in recognition manuals for surface forces. Experimental aircraft had a separate system in the navy based on the year of the Showa reign. In the army the kitai designation was used at the experimental stage and continued for the life of the aircraft though having only secondary use after the aircraft was awarded an official year-type designation. Finally, late in the war the long form designation was abandoned and a system of naming aircraft adopted.

It is not necessary to master the complexity of these various systems to use historically correct designations for the vast majority of Japanese aircraft discussed in popular literature. Perpetuating a system of code-names and using it as though it was universally adopted to the exclusions of Japanese official designations throughout the war may be convenient for some but is historically inaccurate.

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