In Soviet Russia, the term armored forces (thus called Bronevyye sily) preceded the mechanised corps.
During this time, and based on the experience of the Civil War with its sweeping movements of horse-mobile formations, Soviet military theorists such as Vladimir Triandafillov born in Pontus of Greek parents and Konstantin Kalinovsky elaborated the principles of combat use of armored units, which envisioned a large-scale use of tanks in different situations in cooperation with various army units.
But these operations and also observation of the Spanish Civil War, led People’s Commissar for Defence Marshal Voroshilov to the conclusion that the mechanised corps formations were too cumbersome.
This was a mistake, as the success of German panzer divisions in France showed, and in May 1940 Voroshilov was replaced by Marshal Timoshenko.
[1] The decision was reversed, and on 6 July 1940 the NKO ordered the formation of nine new mechanised corps, and in February and March 1941, began forming an additional 20.
[3] However, there was not enough time before the German attack in June 1941 to reform the mechanised corps units fully and for them to reach their former efficiency.
The plan was for each of them to have about 36,000 men and 1,000 tanks, and a few approached that strength level by the time war with Germany broke out.
[8] Such estimation is based on sheer number of concentrated tanks, their main armament, the thickness of their armor,[9] their actual failure rate, the eventual losses to aircraft, and normal scheduled maintenance.
They were about the same size as a German panzer division, and designed as a true combined-arms formation with a good balance of armor, infantry, and artillery.
Total:[12] The listing and data here are drawn from Keith E. Bonn, Slaughterhouse: Handbook of the Eastern Front, Aberjona Press, Bedford, PA, 2005, and V.I.