This will be the first in a recurring series of posts on how aircraft naming/designating systems worked in different countries.  I thought I would start with Japan as the title I’ve chosen for this series has a particular meaning for Japanese aircraft of World War II.

“Zero” may be the best known name representing Japanese military aviation.  But any reading on the subject will quickly expose one to names like “Betty”, “Oscar” or “Kate”.  Just what were Japanese aircraft actually called?

After the jump, what I hope will be a fun little essay.

A colorful and fun children’s book. Just don’t take the text too seriously!

Years ago I remember looking at a children’s book that was called “The Airplane Alphabet Book”.  It had a fun cover, and I’m always a sucker for aviation art so I took a quick look.  I still remember the last page said something like “Z is for Zero.  The Japanese had hard names for their airplanes if you didn’t speak Japanese.  So the Americans made up names like ‘Zero’ to make it easier to know what to call them.”

…

Yeah I’m still stewing on that.  So close, and yet so far away.  The first part is true enough.  But uh, just for the record, Zero was the Japanese Naval Fighter’s real name; and it is the only Japanese aircraft of World War II more widely known by its real name than its Allied code name.

Not quite as colorful inside, but now you can take the text more seriously!

This explanation will be brief.  I apologize if I make any errors in an attempt to simplify.  The best authority on this subject is probably “Japanese Aircraft Code Names & Designations” by Robert C. Mikesh.  Mr Mikesh was head curator of The National Air and Space Museum for many years.  The book has a forward by Maj Gen Frank T. McCoy, Jr (ret).  That’s like really serious name dropping if you’re in to these things.  Gen. McCoy was one of the main designers of the western naming system used on Japanese aircraft.

One thing to keep in mind with aircraft designations, there is usually more than one correct name for any aircraft.  In American usage this usually meant a manufacturer and a military designation.  I’ll get more into this in a few weeks.  But the Japanese often used a short designation, and a longer, more formal one.  And of course the Japanese Army and Navy had completely different ways of arriving at the short designation (So did the US; using the same series of “F”, “B” and “C” numbers is a post-war convention).

The Army was simpler.  For a short designation every aircraft received a “Ki” number.  I believe this was just pure sequential order they were bought by the military.  The good part of this is its pretty easy to just tell a “Ki-27” is a pre-war type and a “Ki-107” is something pretty late.  The bad news is, there’s no type differentiation, so the short designation tells you pretty much nothing else.  But then there was the “formal” name.  The Ki-43 was also known as the “Nakajima Army Type 1 Fighter Hayabusa”.  The “type” part is the last digit of the year on the Imperial calender; “1” means 2601 Imperial, which happens to be 1941 AD (uh sorry, I don’t believe in “CE”).  Also note that the numbering reverted to single digits with the “new century” of 2601; a plane ordered in 2599 (1939) was a “Type 99” while one ordered in 2600 (1940) was, oddly, a Type 100.  So the long designation tells us we have a Nakajima built Army aircraft that entered production in 1941, and its a fighter.  The last part, “Hayabusa” in this case, is just a name.  Hayabusa means Falcon. Fairly big changes might get a new “mark” number, and there also could be a sub-type designator like “Ko” “Otsu” or “Hei” which I believe is just identical to our “A” “B” or “C”.  So a late war Hayabusa might be written out as Ki-43 II Hei.

Short Name: Ki-43 I Ko
Long Name: Nakajima Army Type 1 Fighter Hayabusa
Allied Name: Oscar

The Imperial Navy short designation is actually designed similarly to the US Navy system, but all the type letters are different.  So one famous type would have a basic short designation of “A6M”.  This means the aircraft category is an “A” (fighter), and its the 6th “A” type ordered by the Navy; further, it was built by “M” (Mitsubishi).  So similarly, the “D3A” would be the 3rd dive bomber type built for the Navy; it was built by Aichi (In the US system, the number is by manufacturer, for the Japanese it was total for all manufacturers).  Unlike the Army short designations, the Navy system actually gives you a lot of information if you know the type and manufacturer codes.  But it doesn’t stop there.  Another number would signify a sub-type.  So the A6M2 would be the 2nd sub-type of the A6M.  The Japanese felt the need to be more specific yet!*  Some one decided (?) more information was needed for the “short” designation.  After the sub-type would come a “model” indicator to show what exact equipment was in use.  So the A6M2 gets a “Model 21” added to it.  This is pronounced “two-one” (NOT twenty-one!) as it indicates the plane is using wing/airframe design two and engine design one.  The next variant was the A6M3 Model 32 showing it was the third sub-type, with the third wing design and second engine.  But the type three wing proved unpopular (I’ll get more into this when I actually am doing a post on the specific airplane!) so they reverted to the previous wing; and most A6M3s produced were the later Model 22s (yes, the Model 22 was produced after the Model 32).  Should I explain how we got to the A6M5 Model 52c?  (There were four sub-types of Model 52 that varied mostly just in armament; 52, 52a, 52b, 52c).

Short Name: Ki-46 III
Long Name: Mitsubishi Army Type 100 Command Reconnaissance Plane
Allied Name: Dinah

So now I can start on the long Imperial Navy designation…

In a nutshell, they did about the same thing as the Imperial Army, except they reverted the dates to single digits in 2600 (1940) instead of 2601 (1941).  The previously discussed A6M had a long name of “Mitsubishi Navy Type 0 Carrier Fighter”.  The “Type 0” means exactly what it would for an Army aircraft, only the format is slightly different (“0” instead of “100”). It was ordered into production in Imperial year 2600 (1940).  The “Carrier” part just means it was designed for aircraft carrier operations, most would actually serve ashore.  It often was called the “Zero-sen” or “Rei-sen” by pilots.  In both cases “sen” is a shortened form of the Japanese word for “fighter”; and “Rei” comes from the Japanese for “Zero”. So pilots most often were calling their plane the “Zero Fighter”. But notice this means there were a lot of completely different “Type Zeros” in Japanese Navy service (every type ordered into production in 1940).  We do need to look at the whole name to know what the heck airplane we’re talking about.  Errr, or the short designation…

So, you got all that?  When World War II started, virtually no one outside of Japan knew any of it.  Not only was Japan extremely secretive, but even into the late 1930s Japan was simply not respected as a world leader in aircraft design.  And contrary to what some may say, this was not just simple racism.  As late as 1937 Japan was still buying aircraft from Britain, Italy, The United States and Germany to fight its wars in China and Mongolia.  Japan wasn’t respected, because it hadn’t earned its place yet.  The aircraft Japan entered World War II with were, in every case, only the first or second generation of aircraft in their category that were ready for the world stage.  It is truly amazing the breakthroughs that had occurred in a short period to make Japan competitive.  It has even been said the Zero Fighter alone was responsible for Pearl Harbor.  There is no doubt it was the weapon that gave Admiral Yamamoto the confidence to initiate the Pearl Harbor operation.

Short Name: A6M5c Model 52c
Long Name: Mitsubishi Navy Type 0 Carrier Fighter
Allied Name: Zeke

So what do you do when you find yourself at war with an opponent you know so little about, you don’t even know what any of their airplanes are called?  Well apart from the obvious; contact everyone you can think of who might have any shreds of useful information, study aircraft crash sites, try to get a hold of some captured examples. It was obvious there was a lot of confusion about Japanese equipment and capabilities.  So a process was started to rationalize what was known.

But given that so little was actually known about what the Japanese were doing and what they had, it took time for much to happen.  The US Air Intelligence Unit in Australia became the first to start assigning names to those types of aircraft identified.  Initially, it was so-called “hillbilly” names like Zeke, Val, Rufe that were used.  Eventually, the list grew long and they wound up using names of everyone in the office.  Quickly Washington and London picked up this system and it was made “official”. The first real rule was just that Fighter types would get boy’s names, while Bomber types would be named for girls.  This was later refined to add girl’s names starting with a “T” for transports, and trees for trainers.  The only exception I know of was when the rocket powered suicide bomb (Yokosuka MXY Ohka) was identified it was named “Baka”, which is Japanese for “idiot”.  I’m not sure if that would be a masculine or feminine idiot…

There were many pit falls in this process; like many types the Japanese never used, getting names.  It was rumored they had whole squadrons of German Bf 109s, so that type got the code “Mike”; but apart from a couple examples purchased for testing, the Japanese never used this type.  There were also types that were never noticed by allied intelligence, like the excellent Ki-100.  I’ll have more of that story when I post the type.  It also happened, more than once, that the same type would be identified by different HQs at about the same time, and be given different names.  This sort of thing was always sorted out, but it often took time.  I will share many of these naming stories in the years to come as I get to various Japanese types.

The legacy of these code names is twofold.  First, Gen. McCoy went on to develop a similar naming scheme during the Cold War for identifying Soviet aircraft types.   Second, and more pertinent to this site, the Japanese aircraft code names became better known, in every case except one spectacular exception, than the original “real” names.  To this day a majority of what is written about the Pacific War, including much post-war Japanese material, uses the code names for Japanese aircraft.  On this site, I will use a fairly common composite system.  I will title each post for Japanese aircraft using both the correct short designation and the Allied code name for the type.

This my longest post at this site to date!  I expect others of these “essays” could also get lengthy.  But all things considered, this is a pretty brief treatment of this subject.  I apologize if my brevity causes problems, I’m happy to explain more if there are questions.  But I think I’ve covered the basics pretty well.  Most other countries had much simpler systems.  Even the US, which is well known for pointless bureaucracy, may generate a much shorter post on this subject when I get to it.

* – I beg the reader not to take my tone as insulting or disparaging in any way.  I work for the US Government.  I find great humor in bureaucracy run amok. Perhaps this whole Essay is something only a government employee can truly appreciate.  I was tempted to add a “Humor” tag to this whole post.

~ up next: the Hawker Hurricane Mk I