The Soviet plan called for the 5th and 6th Guards Armies, and the 53rd Army, to attack on a 30-kilometer wide sector, supported by a heavy artillery concentration, and break through the five successive German defensive lines between Kursk and Kharkov. The former two armies had borne the brunt of the German attack in Operation Citadel. Supported by two additional mobile corps, the 1st Tank Army and the 5th Guards Tank Army, both mostly re-equipped after the end of Operation Citadel, would act as the front's mobile groups and develop the breakthrough by encircling Kharkov from the north and west.