'Concert' (i) was a Soviet partisan undertaking against German railway communications with the object of disrupting the German movement of supplies and reinforcements toward the front during the 'Battle of the Dniepr' and the 'Smolensk Strategic Offensive Operation', otherwise 'Suvorov', in the direction of Smolensk and Gomel (19 September/1 November 1943).

The partisan forces of the Belarus, Karelia, Kalinin, Lithuania, Latvia, Estonia and Crimea regions participated in this very far-ranging operation, which had operational and even strategic implications, and involved 193 partisan detachments and groups totalling more than 210,000 men, women, and children. The operation was undertaken over an area 560 miles (900 km) along the front, excluding Karelia and Crimea, to a depth of 250 miles (400 km) behind the front. Despite adverse weather conditions, which allowed the airlift of less than a half of the planned supplies to the partisan base areas, the operation led to a decrease of some 35-40% in railway deliveries to the German forces, and was thus very significant in the success of the Soviet military operations in the autumn of 1943.

In Belorussia alone the partisans claimed the destruction of more than 90,000 rails, 1,061 trains, 72 railway bridges and 58 Axis garrisons. According to Soviet accounts, 'Concert' (i) also cost the Axis forces more than 53,000 men.