Wednesday, March 15, 2017

Theorem on Newly Discovered Tanks

   As of late, I have uncovered photos of Japanese tank training in Manchuria sometime in 1937 at a photograph auction. At first I regarded this as just another photographed album of pictures of the inter-war period, but, looking through the album, I came across a photo which deeply intrigued me. Two tanks of unknown design, being tested climbing a rise in the fields outside the Manchurian Tank School. At first glance, I had presumed them to be both Chi-Ha tanks as they fit the typical Japanese medium tank style. Further analysis, however, made me believe that these were not Chi-Ha tanks, rather, two brand new designs of tanks as yet unknown. Consulting with some of my colleagues on this, I have since connected some dots in Japanese tank development history that were previously left unnoticed with the research community. Here today I present my new thesis regarding the steps the Japanese most likely took when producing their tanks.

Two New Medium Tanks I recently discovered through a photograph auction. 


The Empire of Japan, like other nations, had their own style of classifying things in the military. Japan used the Imperial Calendar when naming weapons and vehicles in the military under the year of enacted service or construction. It emphasized using the last two (or three) digits of the given year as a Type in number form. A common example of this was the Type 95 Ha-Go tank. The Type refers to the fact the given vehicle belonged to the military. The two digit number following the Type meant that the tank was built in 1935 (Imperial Year 2595). This was standard issue for all things in the military, and would follow through to even the current year.

Type 95 Heavy "Ro-Go".
Prior to the Battle of Shanghai in 1937, the Japanese used a specialized system for labeling tanks. Instead of using a class system to label tanks under specific weight groups like Light, Medium, Heavy, etc, they merely used the order in which they were built. The first Japanese tank built in significant numbers had been the Type 89 I-Go, produced in 1929. It had been the Japanese tank that began mass production for the military, and was named accordingly. I-Go is translated to First Domestic Tank in the Japanese Army. “I” representing First, and “Go” for Domestic [vehicle]. This had been applied to produced tanks until 1937. Three known tanks used this system;

I-Go: First Domestic Tank
Ro-Go: Second Domestic Tank
Ha-Go: Third Domestic Tank

The Ro-Go is commonly known as the Type 95 Heavy Tank. Until 2015, the heavy tank was simply referred to as a heavy tank due to no found naming term applied to it. However discoveries with the O-I documentation release confirmed the tank was given the name Ro-Go, as it was the second tank in Japan produced in numbers outside one or two. It was never labeled as a heavy tank in name, only in its description. Hence the common theory arose that the tank was only referred to as the Type 95 Heavy, instead of the proper name Ro-Go. Other tanks such as the Type 94 Te Ke were not included in this nomenclature due to being a tankette, classified as an armoured car. Hence only three tanks were given naming.

Starting in 1937, the Japanese enacted this new nomenclature starting with the Chi-Ha tank, with the new system being  called the Iroha Naming Convention. Replacing the previous system where tanks were named in their domestic order, they were instead classed under their weight and the number in which they followed through in order. The Chi-Ha, for instance, is translated as “Third Medium” in the army. Other tank classes were given their own names in Kanji and the respective numbers:

Weight Terms:
Chi-Ni Medium Tank. 

Ke: Light
Chi: Medium
Ho: Gun Tank
Ju: Heavy
O: Super Heavy
Shi: Car

1: I
2: Ro
Chi-Ha Medium Tank.
3: Ha
4: Ni
5: Ho
6: He
7: To
8: Chi
9: Ri
10: Nu
11: Ru
12: O

Popular Examples of the Iroha system:

Ke-Ni: Fourth Light
Chi-Nu: Tenth Medium
O-I: First Super Heavy
Chi-Ri: Ninth Medium

Holes in History

The glaring issue with this system was that the Chi-Ha had been labeled the Third Medium tank, despite there being no First and Second Medium tank (I and Ro). Many historians came to the commonly agreed upon conclusion that since the system was only applied to tanks produced from 1937 onwards, the vehicles prior to this were not given the integrated naming change. Japan had produced two medium tanks with the old classification system, the Experimental I tank, which was classed as a medium-like tank, and the Type 89 I-Go. With no knowledge of any other tanks, it was believed the Japanese considered these two tanks the predecessors of the Chi-Ha, and falsely labeled the Experimental I and I-Go tanks as the “Chi-I” and “Chi-Ro” tanks respectively.

Of course, there were problems in this common interpretation that were left unanswered. The Type 98 Ke-Ni, dubbed the Fourth Light Tank, was the first Japanese light tank design  with the new Iroha classing nomenclature. The Ha-Go, which was referred to as the Third Domestic light tank in Japan, had too been incorrectly placed before the Ke-Ni in the Iroha naming system. This left a gap in light tank development that had simply been left unfilled. The lack of documented records with early Japanese tank history had given many historians decades later the trouble of securing a firm timeline of tank development and naming.

Tank "A".
As I mentioned earlier, two new tanks were found that did not match known tanks of the Japanese military. The fact that these two tanks existed in 1937, and had not been commonly known to the world only connects the hiccups in the applied Iroha system. These two tanks, which I for now I will refer to as Tank “A” and Tank “B”, logically fill the spots for the First and Second Medium tank naming that was incorrectly put with the Experimental and I-Go. During the mid ‘30s, Japan began developing a medium tank to became the new battle tank to support the infantry in the field. A series of prototypes were proposed take the spot. The two most known were the Chi-Ha and Chi-Ni tanks. While the Chi-Ha took the role, the Chi-Ni was labeled as the Fourth Medium tank as it was built after the Chi-Ha. However if these two tanks are in fact mediums that were also considered for the role, it is safe
to presume them to be the first series of tanks to compete for
 the role as Japan’s new battle tank.

Tank "B". 
One of my work colleagues, by the name of David Lister (Listy), had two years ago, uncovered more tanks that were produced in Japan during the interbellum period. Hidden within the British archives were a series of heavy and light tanks that according to documents of multiple nations (such as Britain, Japan, Sweden, Australia, America, and Russia) were produced in small numbers and serviced throughout the Chinese mainland and Pacific islands. With these tanks are three light tanks, all supposedly built. If the two tanks I uncovered are truly the Chi-I and Chi-Ro, this even further supports the theory as the three light tanks fit perfectly into the Iroha system where the Ke-Ni is the Fourth Light, with no known predecessor to fit the first three spots as circumstantial evidence supporting my theory.

In this new proposed theory, every spot in the Iroha classing system falls into their proper order up until the 1944-1945 gap where many tanks were scrapped and remain unknown.

Chi-I:  (Medium First) Tank “A”
Chi-Ro:  ( Medium Second) Tank “B” 
Chi-Ha: ( Medium Third) Type 97 Chi-Ha
Chi-Ni: (Medium Fourth): Type 97 Chi-Ni
Chi-Ho: (Medium Fifth) Type 98 Chi-Ho
Chi-He: (Medium Sixth): Type 1 Chi-He
Chi-To: (Medium Seventh): Type 4 Chi-To
Chi-Ri: (Medium Ninth): Type 5 Chi-Ri
Chi-Nu: (Medium Tenth): Type 3 Chi-Nu

Ke-I: (Light First) Unreleased Tank*
Ke-Ro: (Light Second) Unreleased Tank*
Ke-Ha: (Light Third) Unreleased Tank*
Ke-Ni:  (Light Fourth) Type 98 Ke-Ni
Ke-Ho: (Light Fith)  Type 5 Ke-Ho
Ke-He: (Light Sixth) Currently Unknown
Ke-To: (Light Seventh) Type 2 Ke-To
Ke-Ri: (Light Ninth) Type 3 Ke-Ri
Ke-Nu: (Light Tenth) Type 4 Ke-Nu

Ju-I: (Heavy First) Type 96 Heavy*
Ju-Ro: (Heavy Second) Type 97 Heavy*
Ju-Ha: (Heavy Third) Mitsu-104*
Ju-Ni:  (Heavy Fourth) Ishi-108*

* = Tanks currently not publicly available. Kept private with David Lister and I until his book, which was recently contracted, is published.


  1. Wow nice find 'v')b
    I admire your dedication on this topic and these obscure lesser known tanks in general

  2. Type 95 I-Go, Type 95 Ro-Go, Chi-I ("Mystery Tank A"), Chi-Ro ("Mystery Tank B"), Ke-I, Ke-Ro, Ke-Ha, Ke-He, Ju-I, Ju-Ro, Ju-Ha, and 13 native Japanese tanks with unavailable or little-known information still to be added? Sweet.

  3. When can we expect the book to be published. Cause right now is no reel good book on Japanese armor

  4. He told me its getting finalized, so expect within the upcoming couple months!

    1. This comment has been removed by the author.

    2. Do we have a book title or anything to go by? Japanese tanks greatly interest me and I'd love to read David's book, but I'm forgetful and will probably not remember this site exists.

  5. This really is fascinating, I didn't realize there were so many different vehicles yet to be rediscovered in digging through the archive. Thank you for bringing this up.

    Also, I'm definitely looking forward to David Lister's book - maybe when it gets published, someone will finally get around to updating the Wikipedia page for the O-I and people will stop asking about the supposed 120t and 140t versions.

  6. Looking forward to the publication of David's Book, cant wait for more Japanese tanks to be brought to light after so long. Super stoked :D

  7. Thank you so much. Enjoyed the article.

  8. What about the tank destroyer/assault gun series? Any info on them?
    So far the internet only holds little information about them.

    Ho-I : First TD/AG (75mm Mountain Gun mounted on a Chi-He)
    Ho-Ro : Second TD/AG (The 150mm SPG)
    Ho-Ha : Third TD/AG (Unknown?)
    Ho-Ni : Fourth TD/AG (Ho-Ni I, II, III)
    Ho-He : Sixth TD/AG (Unknown?)
    Ho-To : Seventh TD/AG (found this little guy is it really him?)
    Ho-Chi : Eighth TD/AG (Unknown?)
    Ho-Ri : Ninth TD/AG (Those chicken scratches found on the internet)

  9. This comment has been removed by the author.

  10. Indeed your research and your friend's upcoming book is impressive. Might I note that this content could help Wargaming with the japanese tech tree in World of Tanks. In fact, you cold contact them after everything is done and arrange some sort of agreement about sharing your discoveries. World of Tanks is a game that insipires many people into tank research, including me, of course.

  11. Where does the name of the Chi-Se come from? I don't see you mentioning the "Se" as any of the numbering.

  12. Am I correct in assuming that there was no "Chi-chi" tank? Since the word chichi already has a number of meanings.

  13. I guess "Medium tank A" is Observation tank "Ka-So"(指揮戦車カソ), and "medium tank B" is Observation tank "Shi-Ki"(指揮戦車シキ) (this image from "Nihon-no-Sensha"1978, P.180)
    Ka-So's turret is not offset because it based Type 1 MT, and Chi-Ki's turret is offset because it based Type 97 MT

    1. But it seems propaganda photo.(look at right Bottom side of this image)
      Japanese often retouchthe photo, so this will be “photoshopped” photo.
      (Famous retouching example:, Ha-Go with 57mm photo)

  14. せん しゃ
    戦 車 = sensha = tank (military)

    マ ニュ ア ル = ma nyu a ru = manual (instructional or operational)