The 'Kaluga Offensive Operation' was the Soviet fifth of the six sub-operations together constituting the 'Moscow Strategic Offensive Operation' (17 December 1941/5 January 1942 ).
Involving General Leytenant Ivan G. Zakharkin’s 49th Army, General Leytenant Ivan V. Boldin’s 50th Army and General Leytenant Filipp I. Golikov’s 10th Army of General Georgi K. Zhukov’s West Front, the operation was intended to defeat Generaloberst Heinz Guderian’s 2nd Panzerarmee and Generalfeldmarschall GŁnther von Kluge’s 4th Army of Generalfeldmarschall Fedor von Bock’s Heeresgruppe 'Mitte', and to develop an offensive to retake the German-occupied towns of Kaluga, Likhvin and Sukhinichi.
To the north of Tula, Zakharkin’s 49th Army launched an offensive on 14 December and after defeating the right-flank formations of von Kluge’s 4th Army, operating on the eastern bank of the Oka river, liberated Aleksin on 17 December. At the same time, an offensive was launched in the direction of Tarusa and, after crossing the Oka river, on 18 December became embroiled in fighting on the outskirts of Tarusa.
As a result of the Soviet counter-offensive near Tula, Guderian’s 2nd Panzerarmee had lost its overall cohesion: the Panzer army’s main forces withdrew to the south-west in the direction of Orel, while General Walther Fischer von Weikersthal’s left-flank LIII Corps pulled back to the west. By the evening of 17 December, the gap between the two groups had increased to 18.5 miles (30 km).
Zhukov ordered the creation of a mobile group as part of Boldin’s 50th Army but under the command of the army’s deputy commander, General Major Vasili S. Popov. This moved onto the offensive on the night of 17/18 December and, without becoming involved in combat, the mobile group (154th Division, 112th Tank Division, 31st Cavalry Division, two batteries of a guards mortar battalion, one flamethrower company, the Tula Workers' Regiment, one separate tank battalion and some other units) moved in secret to the north toward Kaluga, which it reached late on 20 December. On the morning of 21 December, the mobile group captured the bridge over the Oka river and entered Kaluga, where it entered urban combat with the town’s garrison (Generalleutnant Friedrich Bergmann’s 137th Division and units of Generalleutnant Wilhelm Ritter von Thoma’s 20th Panzerdivision). There as fierce fighting, which threatened the complete destruction of the mobile group. The 258th Division of the 50th Army, providing cover for the mobile group, met resistance from Generalmajor Gerhard Berthold’s 31st Division in the area near Titovo.
Nevertheless, by 23 December the 50th Army’s main strength was nearing Kaluga. The I Guards Cavalry Corps reached Odoyev to the south of Kaluga, and the German forces along the road linking Kaluga and Tula were driven sharply back by theSoviet advance from the south. At dawn on 30 December, Soviet troops stormed Kaluga’s railway station, which the Germans had turned into a strongpoint as the centre of their defence. Kaluga was liberated on 30 December.
Between 1 and 6 January 1942, the 49th Army, 50th Army and I Guards Cavalry Corps fought the 4th Army, which was concentrated in the area of Yukhnov and Kondrovo. Until 6 January, right-flank formations of the 50th Army fought unsuccessfully to take the settlement and the Tikhonova Pustyn junction, while the same army’s left-hand formations advanced between 9.3 and 15.5 miles (15 and 25 km) in the direction of Yukhnov, but on 6 January these formations were stopped by the Germans, who had transferred one Panzer division to the area of Yukhnov. Early in January, the 49th Army fought fierce battles to the east of the railway linking Maloyaroslavets and Kaluga, and reached Detchino, which it liberated on 9 January.
As a result of the 'Kaluga Offensive Operation', the Soviet forces advanced between 74.5 and 81 miles (120 and 130 km,) liberated Kaluga, Belyov and Kozelsk, and reached a line extending from a point to the east of St Tikhonova Pustyn to Belev via Zheleztsovo, Poroslitsy, Zubovo, Frolovskoye, Sukhinichi and Volkonskoye before the end of the operation on 5 January.