 Complete the following phrase:  The operational method revolved around outmanoeuvring their opponents. The nature of the bulge meant the Red Army could build strong fortifications in depth along the German axis of advance. Two rifle divisions defended the first belt, and one defended the second. A first belt division would only defend an area of 815 kilometres wide and 56 kilometres in depth. Successive defence belts would slow German forces down and force them to conduct slow and attritional battles to break through into the operational depths. Slowing the operational tempo of the enemy would also allow the Soviet intelligence analysts to keep track of German formations and their direction of advance, enabling Soviet reserve formations to be accurately positioned to prevent German spearheads breaking through each of the three main defence belts. Intelligence would also help when initiating their own offensives 