O-I Superheavy Tank: A Complete History

The Battle of Khalkhin Gol had been a devastating defeat for the Empire of Japan in 1939. The Kwantung Army suffered total strategic defeat at the hands of the Soviet Union surrounding the village of Nomonhon. This had been Japan’s first significant deployment of armour against a modern army. Tank development in Imperial Japan was still in its nascent stages by the time the border conflict at Nomonhon began.

Notebooks belonging to the engineers working on the O-I/Mi-To tank project, and
where majority of the source material from this write-up derived from, including all drawings.

Tank Battle of Khalkhin Gol

It was the eve of June 20th, and the Japanese headquarters in Manchukuo enacted emergency mobilization of the 3rd and 4th Tank Regiments. Soviet armies moved alongside the Manchurian border, preparing to retaliate for the border skirmish between Mongolian calvary units under supervision of the Soviet Union, and Manchurian infantry regiments. A border dispute between two puppet states forced the response of the Empire of Japan and Soviet Union to mobilize their borders.

Japanese Tank Regiment's pushing around the Harzha River to the frontline.