Author: SoukouDragon Probably the most famous Japanese heavy tank is the O-I, a 120 ton multi-turreted gargantuan monstrosity. There is something appealing to it to say the least. But maybe it was actually 140 tons. There reflects the difficulty about this tank. To get started, I find it might be helpful to draw out the full extent of Japanese heavies. It could help put things in perspective. So real quickly, here is a list of all Japanese heavy tanks possible for WoT with a few handy facts for each. All are multi turreted except for the noted Heavy X which I do not know anything about. Armor is listed in a front/side/rear format if the numbers are available. Otherwise just the maximum armor is given. The 100 ton and the O-I will be discussed afterwards. Type 91 Built: 1 Date: Around 1931 Crew: 5 Main Armament: Short barrel 70mm Weight: 18 tons Engine: 224hp Armor: 20mm Based off Japan’s very first tank, the Experimental 1 tank. Type 95 Built: 4 Date: 1935 Crew: 5 Main Armament: Short barrel 70mm Weight: 26 tons Engine: 290hp Armor Turret: 30/25/25 Hull: 35/30/25 Improved firepower via forward mini-turret mounting a 37mm cannon. Improved armor and suspension redesigned. 100 ton Built: 1 Date: 1940 (failed mobility testing) Crew: 11 Main Armament: 105mm cannon Weight: 100 tons Engine: 550hp x2 for combined 1,100 hp Armor: Front hull: 150mm Side Hull: 70mm Top secret project initiated right after the Japanese suffered defeat from the Soviet Union in 1939. O-I Built: 1 (either completed or incomplete prototype) Date: Started in 1944, unclear how long the project lasted. Likely until August 1945 Crew: 11 Main Armament: 105mm cannon Weight: 120 or 140 tons Engine: 550hp x2 for combined 1,100hp Armor Turret: 200/200/200 Hull 200/110 or partial 75 and partial 35/150 Probably intended for Manchuria. Heavy X WG stated that a tank for tier 10 has been found. It was stated as huge and massive but still not heavier than the Maus. There is no official name that I know of. The information that follows comes from multiple sources. The core parts all match but there are some inconsistencies. It is difficult to say which is true or false. The facts in the sources are mostly from what was described by those involved or on rumors. There are very little primary sources available like photos or complete original blueprints that could enable more consistency on available information. However Suzuki from Finemolds does have a collection of primary sources on the 100 ton tank. Aside from Suzuki, the other sources themselves often indicate how some history or technical details are speculated and remain unconfirmed. Some sources present information not giving in the other sources. So here will be a list of the sources along with reference abbreviations in parenthesis so that the reader can know where each bit of information is coming from after a little familiarization. I am afraid that while very interesting, reading this might be difficult to grasp at first because of all the different sources. Pacific War Secrets: All Japanese Secret Weapons (JSW) Imperial Japanese Army Land Weapon Guide (LWG) Tank and Tank Battles (TTB) Japanese Tanks (Hara – The primary author) Suzuki’s pictured sources (Suzuki – Has the only primary sources from what I understand and thus likely to be the most accurate of all. Well, there could be more primary sources that are still being held secretly) The Phantom 100 ton Super Heavy Tank Below is from a section in TTB unless stated otherwise. The writer of this section is Shigeo Otaka who was a Mitsubishi engineer involved in the 100 ton tank’s development. He states that in this section he applied information from other people involved in the project but due to the passage of time and the secret nature of the military program, he is unable to give a complete description of the tank. The description is made only from collective memories of those involved however the main features can be described. The project was under the supervision of Colonel Murata from the 4th Technical Research Head Quarters. JSW says that Colonel Iwakuro from the Department of War gave the order to build the monster. The order to build the 100 ton tank came immediately after the defeat against the Soviet Union in the Nomonhan incident in 1939. LWG gives a quote from a position and ranked officer that is the same as Colonel Iwakuro but does not gave the officer’s name. Probably still Iwakuro. Quote and picture of Iwakuro below. 「満州の大平原で移動トーチカとして使えるような巨大戦車を作ってほしい。極秘でだ。」 “I want a huge tank built which can be used as a mobile pillbox in the wide open plains of Manchuria. Top secret.” Here is another quote from LWG of an undisputable requirement from the Colonel. 「今の戦車の寸法を2倍に延ばして作れ」 “Make the dimensions twice that of today’s tanks.” Hideo Iwakuro: Shigeo Otaka and several others were guided multiple times throughout a wooden barracks that used to be the headquarters of the 4th Technical Research Group, sometimes crammed together in small rooms. Under strict rules to speak of nothing of what will be seen, the group of people was finally led to a secret room. The room had a two door entrance to reduce the chance of eyes catching a glimpse of the interior. Nobody outside of the room knew what was going on. Here, the plan was pulled out in lots of random pieces. It was an effort for the group just to bring all the pieces together but eventually the secret tank image appeared. There were some concerns whether the tank would be able to move or how it could be transported but those concerns were kept individually private. However, the behemoth was both imposing and impressive. Total length was 10 meters. Total width was 4.2 meters, and total height was 4 meters. Height without the turret was 2.5 meters. Track width was 900mm. The power plant was two 550 horsepower air-cooled gasoline engines for a combined horsepower of 1,100hp. Top speed was 25kph. This section from the TTB writes that the army called it the O-I and Mitsubishi called it Mi-To (Mitsubishi-Tokyo). Hara, JSW, and LWG call only the 120 ton tank the O-I so TTB could be mistaking here. JSW and LWG say the O-I was called Mi-To and not the 100 ton tank. Hara does not mention “Mi-To” but does say that both the 100 ton and the O-I were developed by Mitsubishi. Perhaps both were actually called Mi-To. At least according to Hara, the “Mi” part is true for both. Maybe both were also made in Tokyo. JSW says that according to one rumor, that when the O-I was completed, Continue reading →

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