Comparing: O-Ni vs. T29

A further development of the O-I with improved anti-tank guns. The military command's plan was to improve the earlier models and achieve a higher level of armor protection on the vehicle. Existed only in blueprints. No finished prototypes were built and the vehicle never saw action.

Development of this experimental heavy tank started in 1944. The prototype was built in 1947. The vehicle featured the 105 mm T5E1 gun. After the war, the mass production of heavy tanks was deemed unreasonable, and only a few prototypes of this vehicle were built.