The 'Sea of Azov Defensive Operation', known to the Germans as the Battle of the Chernigovka Pocket, was the unsuccessful Soviet attempt to halt an Axis offensive along the northern coast of the Sea of Azov toward Rostov-na-Donu (29 September/11 October 1941).

The operation was, during the time of the 'Barbarossa' campaign, the most south-easterly element of the German invasion of the USSR and was known to the Soviets as the Battle of the Sea of Azov within the 'Donbass-Rostov Strategic Defensive Operation' of 29 September/16 November. The other sub-operation of this strategic defensive was the 'Sumy-Kharkov Defensive Operation' of 30 September/30 November, which included the 'Defence of Kharkov Defensive Operation' of 20/24 October.

The death or capture of two-thirds of all the men of the South Front in four days unhinged the front’s left flank, allowing the Germans to capture Kharkov on 24 October. von Kleist’s 1^st Panzerarmee took the Donbass region in that same month, while von Manstein’s 11^th Army was freed from 18 October to take Crimea.

After concluding the Battle of Kiev in September 1941, Generalfeldmarschall Gerd von Rundstedt’s Heeresgruppe 'Süd' advanced from the Dniepr river to the north coast of the Sea of Azov. The city of Rostov-na-Donu, on the mouth of the Don river, was assigned as the objective for the 11^th Army, then under the command of Generaloberst Eugen Ritter von Schobert: this officer was killed on 12 September when his Fieseler Fi 156 Storch liaison/reconnaissance aeroplane landed in a minefield. To replace von Schobert, General Erich von Manstein, commander of the LVI Corps (mot.), was ordered to travel from the Leningrad sector to the extreme southern sector.

At this time General Erik Hansen’s LIV Corps of the 11^th Army was still engaged in Crimea, and because the Romanian forces were still committed in the siege of Odessa, the 11^th Army's resources for the assault on Rostov-na-Donu were severely limited even though the Soviet forces were retreating. von Manstein therefore initially replaced the LIV Corps with the smaller XXX Corps and XLIX Gebirgskorps, commanded by General Hans von Salmuth and General Ludwig Kübler respectively, and ordered the LIV Corps into the first echelon of the advance to Rostov.

Late in September General de corp de armatâ Petre Dumitrescu’s Romanian 3^rd Army joined the 11^th Army in the advance to Rostov-na-Donu, but was then severely depleted by the attacks of General Major Fyedor M. Kharitonov’s 9^th Army and General Leytenant Andrei K. Smirnov’s 18^th Army on 26 September. This forced von Manstein to halt his advance as his left flank was threatened, and forced him to use his only mobile reserve unit, SS-Obergruppenführer und General der Waffen-SS Josef Dietrich’s SS Brigade 'Leibstandarte Adolf Hitler' to bolster the Romanian defences.

After the arrival of the SS unit had stabilised the Romanian sector, the Soviets increased their pressure on the XXX Corps. The Soviets did not respond to the build-up of Generaloberst Ewald von Kleist’s 1^st Panzergruppe, on 11 October redesignated as the 1^st Panzerarmee, on their northern flank. On 1 October the Germans started their counterattack from the north and the west. The rapid advance of the German armoured and motorised formations from the north compelled the Soviets to retreat on 3 October. The 11^th Army took up the pursuit, with the SS unit’s attack eliminating the headquarters of the 30^th Division and dispersing its subordinate units. Melitopol was captured on 5 October by General Eberhardt von Mackensen’s III Corps [mot.), The reconnaissance battalion of the SS unit under the command of SS-Obersturmführer Kurt Meyer captured Berdyansk on 6 October. General Gustav Anton von Wietersheim’s XIV Corps linked with the SS unit to encircle seven Soviet divisions in the Mariupol and Berdyansk area on 7 October. Four days later the battle was over and the 150,000 men of the 9^th Army and 18^th Army caught in the pocket had been killed or captured. The Germans took more than 106,332 prisoners, both in the pocket and during the pursuit, along with 212 tanks and 772 guns of all types. Smirnov, the 18^th Army’s commander, was killed in action and buried with full military honours by the Germans.

The assault on Rostov-na-Donu began on 17 November, and ended on 21 November with the German seizure of the city. However, the German lines were by now considerably overextended, and von Kleist’s warnings that his left flank was vulnerable and that his tanks were ineffective in the freezing weather were ignored. On 27 November, in the 'Rostov-na-Donu Strategic Offensive Operation' (17 November/2 December) General Leytenant Anton I. Lopatin’s 37^th Army counterattacked the 1^st Panzerarmee's spearhead from the north, forcing the Germans to withdraw from the city. Adolf Hitler immediately ordered that the retreat be terminated, and when von Rundstedt refused to obey this order, Hitler dismissed him and replaced him with Generalfeldmarschall Walter von Reichenau. However, von Reichenau immediately saw that von Rundstedt had been correct, and succeeded in persuading Hitler, via Generaloberst Franz Halder, the chef-of-staff of the Oberkommando des Heeres, to change his mind authorise the withdrawal. The 1^st Panzerarmee was then driven back to the line of the Mius river at Taganrog. This was the first significant German withdrawal of the war.

The German offensive along the northern shore of the Sea of Azov was resumed in the summer of 1942 during the 'Blau' campaign, With air support from the Junkers Ju 87 dive-bombers of Major Clemens Graf von Schönborn-Wiesentheid’s Sturzkampfgeschwader 77, Generalfeldmarschall Wilhelm List’s Heeresgruppe 'A' recaptured Rostov-na-Donu, the so-called 'gate to the Caucasus, on 23 July 1942 with relative ease.

Farther to the south along the coast, the remaining small ports and coastal areas still in Soviet hands were captured by Romanian cavalry units, Yeysk falling to the Romanians on 8 August after they had defeated the naval infantry of the Azov Naval Flotilla. the flotilla regrouped at Temryuk. Late in August, as Romanian forces seized the ports of Anapa and Temryuk, most of the flotilla was scuttled at Temryuk on 23 August: at Temryuk the flotilla lost its three primary warships in the form of the 840-ton gunboats Bug, Don and Dniestr. The campaign thus came to an end after bitter house-to-house fighting in Temryuk.

With the Sea of Azov secured, the Axis forces embarked on the 'Blücher II' amphibious operation in a bid to destroy all Soviet resistance on the Taman peninsula and thereby open another maritime line of communication to Crimea.