Sunday, March 5, 2017

O-I Size Comparisons

While I finish up the next history article for you guys, Here is something interesting for those curious about the O-I superheavy tank. I've put together a few diagrams comparing the size of the O-I with popular tanks of other nations many are familiar with.

Built in 1943, the O-I tank was one of the largest armoured vehicles produced, dwarfing even the notorious Tiger tank serviced in Germany during the Second World War. The tank had a height of 3.63 meters, a length of 10.12 meters, and a width of 4.84 meters. The dimensions of the vehicle closely matched those of the Panzer VIII Maus. These proportions were massive and required the equally large amount of crew to operate it. The crew consisted of 11 manned positions. These were; 1 Driver, 1 Co Driver, 3 Main turret gunners, 1 Commander, 2 secondary turret operators, 1 rear turret operator, 1 Radio signaler, and 1 Engineer to maintain the tank. It maintains one of the highest crew count for any produced tank.

O-I with the Tiger I tank (Front View)

O-I, Maus, T-95 (Front View)

O-I, Maus, T-95 (Side View)

O-I and Type95 Ro-Go heavy (Side View)


If someone came to you and asked the question; "what comes to mind when you hear the term super-heavy tank?", the average answer would be the notorious Maus or E-100 respectively. Big clunking tanks with large slabs of thick steel and armed with monstrous cannons. The idea of this class of vehicle had lingered on since the First World War, often relegated to the domain of prototypes and experimental designs. It would not be until the inter-war period that the concept captured designers' imaginations and drawing-boards as the 'next big thing' to turn the tide in the wars to come. Japan was no exception; in the dawn of the 40's, this super heavy tank would be known to the public as the O-I.


The O-I was conceived out of the necessity to produce a mobile bunker to contest the Soviet Union in the then-expected Second Russo-Japanese conflict. The flaw with the routine bunker or pillbox is that you cannot maneuver and relocate them with the frontline constantly being pushed. Japan would need a sustainable fortress that could push with the infantry and advance further into the USSR without the need to construct more immobile bunkers with resources already scarce.



  1. What is that second tank not mentioned in the o-i ro-go comparison, the one without the outline, what secrets does it hold!

    1. TanK? I dont see any such thing!

    2. Sssshhh. No tanks. Only dreams.

    3. Can you give any background on this certain proposed Japanese heavy tank (~100 tons, 105mm gun, a main central turret, & 2 frontal MG turrets):

    4. It never existed. Post war theorizing on what the O-I has actually been.

    5. Is it a German Neubauferzeug Multi-turret Medium Tank?

  2. So how would it compare to the Char 2C?

    1. Some Char 2C gameplay of you're interested:

  3. once again something interesting to "read" (this time was more to "look at"), since you are "touching" the O-I topic again wouldn't it be interesting if you wrote an article about the people behind japanese heavy tank development so that e can understand why they came up with these ideas?
    I would definitly like to know more since at most I've only read small articles about them
    and if you mention how one of them was behind the "japanese" Tiger and submit it to gaijin the article could even end up posted on the War Thunder portal, that would raise awereness from the players about how a japanese heavy tank line is doable

  4. What is that second tank not mentioned in the o-i ro-go comparison, the one without the outline, what secrets does it hold!

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  5. Great work Mai, have you ever seen a realy fotografie from the oi tank?

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