At the start of the Second World War much of the Red Army , including its armoured forces , was in transition and recovering from the 1937 repression of the officer corps . The Red Army ignored the lessons from Nomonhan , which had been successfully conducted by General Zhukov , and relied instead on lessons from politically selected officers who were veterans of the Spanish Civil War . The result was a poor showing during the Soviet-Finnish War of 1939 . The Red Army tank fleet was extremely large , consisting of some 24,000 vehicles , but many were obsolete or unfit for service due to difficulties with supplying spare parts and lack of qualified support staff
1937 repression of the officer corps
Great Purge
Armoured warfare