Short 20-gun self-propelled gun / Super Destroyer for Japan

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Short 20-gun self-propelled gun (短二十糎自走砲)
The short 20-gun self-propelled gun was the Japanese prototype of the self-propelled gun. The construction of two prototype guns began, which were about 20% ready when Japan capitulated.
The Imperial Japanese Navy (IJN) in 1945 developed the Type 97 Chi-Ha Short Gun tank, which was armed with a 120 mm short-barreled howitzer. However, the IJN command required a more heavily armed support vehicle to defend the home islands from American landings. It was decided that a 20 cm/12 short naval gun would be mounted on the chassis of the Chi-Ha tank. The work began in August 1945, although some sources say August 20 is a very unlikely date. The production of the new vehicle was handled by the 1st Military Research Institute and the Military Arsenal in Osaka. By 2 September 1945, the 2 prototype guns were more than 20% ready. At the time of capitulation, all technical documentation was destroyed to prevent it from falling into the hands of the enemy.
Construction description
Unfortunately, before the capitulation of Japan, the designers of the machine destroyed all the plans/designs of this interesting machine, so its appearance and the way of attaching the Short 20 cm/12 naval gun is unknown. However, due to the speed of work (more than 20% of the prototype gun was developed in 1 month), it can be concluded that it was a vehicle very similar to the Type 97 Chi-Ha Long Gun, which was a technically simple modification.It is likely that the hull was to be modified in the same way as in the Type 97 Chi-Ha Long Gun. In addition, it was certainly planned to strengthen the roof so that it could withstand a shot from a powerful 200 mm cannon.
This is what a Short 20-gun self-propelled gun could have looked like^

20 cm/12 short naval gun
The 20 cm/12 short naval gun was to be the main armament of the Short 20-gun self-propelled gun. The gun itself was designed at the same time as the 12 cm/12 short naval gun, but it was not introduced into service until 1943. This gun with a powerful caliber of 200 mm served at first as a universal naval gun, and then it began to be mounted in fortified positions on land. Thanks to its short barrel, it was able to hit targets behind cover. On ships, its main task was to destroy submarines, in addition, it could support anti-aircraft defense with anti-aircraft missiles. The IJN used these guns as coastal artillery. These guns took part in the defense of Palau, Saipan, Guam and Okinawa, where they showed high effectiveness in destroying unarmored targets (soldiers, cars) and armored targets (tanks).

20 cm/12 short naval gun


OIP (1)
OIP (2)
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The ammunition required for the gun was semi-solid and consisted of a 46 kilogram projectile and a copper alloy cartridge (3 kg) containing a propellant. A number of missiles were developed, namely anti-aircraft, anti-tank, high-explosive, incendiary, incendiary, parachute and training missiles.

  1. Semifixed (Name: ?)
  • Length: 56 cm
  • Weight: 55 kg
  • Explosive weight: ?
  • Explosive: Trinitroanisole (type 91 explosive)
  • Fuse: Impact or delayed fuse
  • Warheads: anti-aircraft, anti-submarine, anti-tank (?), parachute (?)
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  1. High Explosive (Name: mk.1)
  • Length: 56 cm
  • Weight: 50 kg
  • Explosive weight: 12.9 kg
  • Explosive: Trinitroanisole (type 91 explosive)
  • Burst range: 24m
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  1. Incendiary-Shrapnel (Name: ?)
  • Length: 56 cm
  • Weight: 47 kg
  • Explosive weight: 14 kg
  • Warhead: 144 tubes of C5 explosive
  • Explosive: Trinitroanisole (type 91 explosive)
  • Burst range: 30m

Unfortunately, I do not have access to data on the anti-tank power of the shells for this gun


  1. Short 20-gun self-propelled gun
  • Length: 5.55 m
  • Width: 2.33 m
  • Weight: ? (probably about 17 tons)
  • Height: ?
  • Top speed: 38 km/h
  • Crew: ? (probably 7 or 8)
  • Operational range: 210 km
  • Engine: Mitsubishi SA12200VD air-cooled V12 diesel, hp/1,500 rpm ,170 hp/2,000
  1. 20 cm/12 short naval gun
  • Length: 2.52 m
  • Weight: 4 t
  • Caliber: 202 mm
  • Crew: 6-7
  • Effective firing range: 3,300 m
  • Maximum firing range: 6,300 m
  • Rate of Fire: 3-5 shots per minute


  • Hull has the same armor as the Type 97 Chi-Ha Long Gun
  • Turret: no armor


  • 1x 20 cm/12 short naval gun (Unknown number of bullets)

A short SPG with 20 guns would be a very interesting vehicle for Japan in War Thunder. Thanks to the powerful caliber of the main weapon, it is able to destroy even very well-armored enemy tanks. In addition, its gun, although it is not a howitzer, is still able to fire stromotor fire, which will allow it to destroy enemy vehicles behind cover. Unfortunately, due to the fact that this is a vehicle at an early stage of the prototype, unfortunately it takes a miracle for this vehicle to get to WT. However, this vehicle would definitely find a place for fans of Japanese technology in War Tunder, which would be good for the Japanese tech tree. I encourage you to discuss in the comments and to share your own knowledge on this subject.
Finally, I apologize for the linguistic and logical errors because unfortunately English is not my main language and I had to use google translator.

Internet sources

短二十糎砲 - Wikipedia
Short Barrel 20cm SPG - WoT妄想日本戦車ツリー Wiki (
短二十糎自走砲とは何? わかりやすく解説 Weblio辞書
Japan 20 cm/12 (8") Short Gun - NavWeaps
20 cm/12 short naval gun - Wikipedia
Technical data of the 20cm short naval gun. Various sources | Download Table (
短十二糎自走砲 - Wikipedia
短十二糎砲・短二十糎砲 | 戦跡の歩き方 (
TM 9-1985-5; 20-cm/Short (202-mm) (8-Inch) Complete Round (Semifixed) (
TM 9-1985-5; (Ordinary Mk 1) 20-cm (202-mm) (8-Inch) High-Explosive (

Book sources

+1 Goofy ahh tank.

Looks like a Japanese Goliath artillery piece 😂

As if the 12cm SPGs weren’t goofy enough! +1

1 Like

You have my +1

I think that Mk.1 HE-round is “anti-tank” enough, lol. No need for any dedicated AP-rounds.

maybe there is no need, but it is possible

Big gun goes BOOM!

Japanese maus

Finally a really really big gun to delete everything that gets in my way

As much as i love japane just no there is too much questionable things in the article and not enough info -1
Also “A short SPG with 20 guns”, needed way more proofreading or basic QC

1 Like

Imagine turning a corner and seeing this
I wonder what a 200mm ap round it has

Did we read something different?? Where did you find “20 guns”???

Maybe type 88 APBC that the old 200mm heavy cruisers used.

20 probably is 200mm

I hope lol

I do wonder if it can use naval shells

Idk much about Japanese tanks

Can the Ha-Go Chasis even carry this huge ass gun?

It’s on a chi ha like the chi ha long gun