First, welcome aboard arminiuss! Citadel would have been feasible in 1941 but not in 1943. Until summer 1943 Red Army has evolved while the Germans attempted to achieve a final victory based on Blitzkrieg strategy. Here is a snippet from Glanz's study "CSI Report No. 11 Soviet Defensive Tactics at Kursk, July 1943" explaining the reasons for the German failure: … the development of strategic and operational defenses depended directly on the Soviet ability to stop German offensive action at the tactical level. Soviet development of effective tactical defenses was a long and difficult process. It involved changing the offensive mind-set of Soviet officers. It also entailed the training of a generation of officers capable of ably controlling forces at the tactical level and the fielding of equipment of the type and in the numbers necessary to conduct successful combined arms defense. Development of tactical defense concepts involved a process of education that began in June 1941 and continued throughout the war. The fruits of that education were apparent at Kursk. Complete study is HERE. PS: Defense at Kursk wasn't just digging trenches and piling-up of weapons and ammunition. The Red Army has adopted completely new doctrine at tactical level. It was just the initial stage of offensive actions which have started shortly after the beginning of "Citadel".