Soviet military analysts and historians divide the war into three periods. The Red Army was primarily on the strategic defensive during the first period of war (22 June 1941 – 19 November 1942). By late 1942 the Soviets had recovered sufficiently to put their concept into practice. The second period of war (19 November 1942 – 31 December 1943), which commenced with the Soviet strategic counteroffensive at Stalingrad, was a transitional period marked by alternating attempts by both sides to secure strategic advantage. After that, deep battle was used to devastating effect, allowing the Red Army to destroy hundreds of Axis divisions. After the Battle of Kursk, the Soviets had firmly secured the strategic initiative and advanced beyond the Dnepr River. The Red Army maintained the strategic initiative during the third and final period of war (1944–1945) and ultimately played a central role in the Allied victory in Europe.