The O-I was Japan's only true heavy tank during WW2. It was designed and put to production in 1943. Its design inspiration is the Soviet T-35 heavy tank, with which it shares a basic layout. Only about 80 were constructed throughout the war, out of which 40 were knocked out in combat, taking a considerable number of American tanks with them. The O-I features 150mm of RHA steel in the front, a main 105mm cannon, two secondary 47mm cannons, and two 7.7mm machineguns (one coaxial and one in the hull). A few were smuggled into Oceanyka after the war, likely as part of a scheme by MacArthur's Allied Occupation to get funds for reconstruction.