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 Winter War. 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. One important development took place shortly before the war, which influenced Soviet armoured doctrine and tank design for a decade: the creation of the T-34. Developed on the Christie suspension chassis and using sloped armour for the first time, the T-34 proved a shock to the German forces in the first German encounter of Soviet T-34 and KV tanks. The T-34 had an excellent combination of mobility, protection and firepower. Using wide tracks, the T-34 was also able to negotiate terrain in difficult weather conditions, something that persistently dogged the German designs. Assessing the success of the German Blitzkrieg strategy, operational methods and tactics, the Red Army concluded that it should return to the use of operational methods developed before the war, so the Tank Armies were eventually created. To complement the T-34, heavy tanks, self-propelled artillery, and tank destroyers were also designed. The Red Army's armoured forces were used in concentrations during all strategic operations of the Red Army in World War II, initiated under strict secrecy and using the Principle of Surprise. Germany In Germany, in-depth research through theoretical approaches, wargaming and exercises developed a confidence within the Panzertruppe itself (and political support by Hitler) in the armoured formation as the key battlefield formation – although this view was before 1940 not shared by the other Arms of Service. A key part of this doctrine was improved communications by having radios in all tanks, although this ideal suffered from technical limits as most tanks had receiver sets only. At the outbreak of World War II, the German armoured forces benefited from a much more profound and more flexible training than that of the Allies on the tactical and operational level. German tanks operated while directed by radio communication, which allowed tank commanders to take greater advantage of the manoeuvrability of