The 'Bryansk Defensive Operation', otherwise known as the Battle of Bryansk, was a 20-day battle fought in the area of Bryansk as the forces of Heeresgruppe 'Mitte' overcame the Soviet forces of the Bryansk Front as the Germans drove toward Moscow within the context of the later stages of 'Barbarossa' (30 September/21 October 1941).

Returning from its diversion from Generalfeldmarschall Fedor von Bock’s Heeresgruppe 'Mitte' to bolster Generaloberst Gerd von Rundstedt’s Heeresgruppe 'Süd' in the seizure of Ukraine, and especially of Kiev, Generaloberst Heinz Guderian’s 2^nd Panzergruppe, which was redesignated as the 2^nd Panzerarmee on 5 October, attacked in an unexpected direction to take Orel on 3 October and Bryansk on 9 October, thereby encircling two Soviet formations, General Major Avksentii M. Gorodnyansky’s 13^th Army and General Major Yakov G. Kreizer’s 3^rd Army of General Leytenant Andrei I. Eremenko (from 13 October General Major Georgi F. Zakharov’s) Bryansk Front. A third Soviet formation, General Mikhail P. Petrov’s (from 13 October General Major Arkadi N. Ermakov’s) 50^th Army was encircled by General Joachim Lemelsen’s XLVII Corps (mot.) and infantry of Generaloberst Maximilian Reichsfreiherr von Weichs’s 2^nd Army, which met on 12 October to the north-east of Bryansk. The encircled Soviet armies continued to fight, however, and this seriously delayed the German assault toward Moscow: this was to have major strategic implications in the new few months as the two-week delay, in combination with the casualties taken by the Germans as they destroyed the Soviet pockets, contributed to the German collapse at the gates of Moscow. As a result of this battle, the Germans occupied Bryansk until they were driven out 17 September 1943 as a part of the 'Smolensk Strategic Offensive Operation', otherwise known as 'Suvorov'.

After the successful encirclement of Marshal Sovetskogo Soyuza Semyon K. Timoshenko’s reconstituted West Front in the Smolensk pocket, the armour of Heeresgruppe 'Mitte' had been instructed to halt so that the marching infantry formations could join it and complete the destruction of the pocket. Farther to the north, the drive of Generalfeldmarschall Wilhelm Ritter von Leeb’s Heeresgruppe 'Nord' had stalled as it advanced toward Leningrad, and Heeresgruppe 'Süd' was struggling to take Kiev, the main city of Ukraine. To secure the flanks of Heeresgruppe 'Mitte', Adolf Hitler ordered the separation of Generaloberst Hermann Hoth’s 3^rd Panzergruppe toward the north and Guderian’s 3^rd Panzergruppe toward the south. The infantry formations of Heeresgruppe 'Mitte', Generalfeldmarschall Günther von Kluge’s 4^th Army and Generaloberst Adolf Strauss’s 9^th Army, were ordered to dig in and wait for their flanks to be secured.

During the interval that now ensued in the offensive of Heeresgruppe 'Mitte', the Soviet general staff ordered the Soviet formations around Smolensk and Bryansk to attack Heeresgruppe 'Mitte' frontally in an effort to drive the Germans back from the approaches to Moscow. The offensives were undertaken over poor terrain against formations and units in strong defensive positions, so almost all of these assaults were disastrous failures which seriously weakened the Soviet formations defending the approaches to Moscow.

In September 1941, Lemelsen’s XLVII Corps (mot.), one of the 2^nd Panzergruppe's four corps, advanced toward and then crossed the Desna river in the area to the south-west of Moscow. During this breakthrough, the Germans penetrated the Bryansk Front on 30 September during the operation to encircle the 50^th Army. This resulted in the emergence of a gap in the front’s positions between the 50^th Army to the north of Bryansk and the 13^th Army to the north of this city. Eremenko adopted a strategy of defence in depth, with the front’s reserves (two infantry divisions, one tank division and one tank brigade) concentrated in the Bryansk area. However, in the course of the operation, the XLVII Corps (mot.) took Sevsk and then Dmitrovsk as its progressed to the north-east, and then wheeled to the north-west to seize Karachev in the area to the south-east of Bryansk, where it linked with General Gotthard Heinrici’s XLIII Corps of the 2^nd Army driving to the east after penetrating through the Bryansk gap. The XLVIII Corps (mot.) then turned back to the north-west to meet other elements of the 2^nd Army, advancing eastward from Dubrovka, at Boyanovichi. This trapped the 50^th Army in a large pocket to the north of Bryansk, while to the south of this city the 3^rd Army and 13^th Army were similarly encircled in a larger pocket.

This forced the 50^th Army, 3^rd Army and 13^th Army, and other elements commanded by Ermakov, to withdraw in order to avoid encirclement, and consequently Bryansk was evacuated without significant fighting. Regardless of this, the city was subjected to heavy artillery and air bombardment which destroyed large parts of it. Starting on 12 October, ty 23 October what was left of the 50^th Army, 3^rd Army and 13^th Army had fallen back eastward to Belyev, south-east to Maloarkhangyel’sk and farther to the south-east an area to the north-west of Kursk respectively.

The Soviets, as part of the 'Orel-Bryansk Defensive Operation' (30 September/23 October) lost more than 80,000 men killed in and around the city, with around 4,062 men wounded or taken ill. Another 50,000 men were taken prisoner before the XLVII Corps (mot.) moved off to the north-east against its next objective, Orel.

Guderian’s 'one-armed' encirclement had made it possible for the German forces to destroy all the Soviet forces defending the south-western approaches to Moscow by opening the way toward Tula. This lay at the centre of the road and railway network to the south of Moscow, and its capture was vital to the Moscow offensive. After the encirclement of the Bryansk Front, Guderian was closer to Tula than any significant Soviet formation, but the delay in destroying the two pockets to the north and south of Bryansk provided the Stavka the time it so desperately needed to rush reinforcements into the region lying to the south of Moscow, and thereby stabilise the front. When Guderian resumed the drive, he failed to capture Tula, and opted instead to bypass the city: this placed a great logistical constraint on the rest of the Moscow campaign. When Iosef Stalin ordered the 'Moscow Strategic Offensive Operation' in December, Soviet control of Tula forced Guderian to withdraw the 2^nd Panzerarmee from Moscow, in violation of Hitler’s direct order. This resulted in Guderian’s dismissal in January 1942.