By late 22 November, the northern and southern Soviet forces linked up at the town of Kalach, encircling some 290,000 Axis personnel east of the Don River.

Instead of attempting to break out of the encirclement, German leader Adolf Hitler decided to keep Axis forces in Stalingrad and to resupply them by air.

On 28 June 1942, the Wehrmacht began its offensive against Soviet forces opposite of Army Group South, codenamed Case Blue.

[7] The responsibility to take Stalingrad was given to the Sixth Army, which immediately turned towards the Volga River and began its advance with heavy air support from the Luftwaffe's Luftflotte 4.

[15] As early as September the Soviet Stavka (high command) began planning a series of counteroffensives to encompass the destruction of German forces in the south, fighting in Stalingrad and in the Caucasus, and against Army Group Center.

[35] Furthermore, during the course of the German offensive between May and November 1942, two motorized divisions, the elite Leibstandarte and the Großdeutschland, were redeployed from Army Group A to the West, to provide a mechanized reserve in case of an Allied landing in France.

[39][42] Preparations for the offensive were, however, far from perfect; on 8 November, Stavka issued orders to postpone the launch date of the operation, because transportation delays had prevented many units from being able to move into place.

[43] In the meantime, units at the front went through a number of war games to practice repelling an enemy counterattack and exploiting a breakthrough with mechanized forces.

[47] On 17 November Vasilevsky was recalled to Moscow, where he was shown a letter written to Stalin by General Volsky, commander of the 4th Mechanized Corps, who urged calling off the offensive.

The Soviet commanders, overruling Vasilevsky, agreed the offensive would not be called off, and Stalin personally rang Volsky, who reiterated his intention to carry out the operation if ordered to do so.

[56] Although Soviet commanders suggested postponing the bombardment due to poor visibility from thick fog, front headquarters decided to proceed.

Although thick fog prevented the Soviet artillery from correcting their aim, their weeks of preparation and ranging allowed them to lay down accurate fire on enemy positions along the front.

[62] The first two assaults were repulsed by the Romanian defenders,[63] and the effects of the heavy artillery bombardment had actually made it more difficult for Soviet armor to navigate through the minefields and terrain.

[76] As German forces began to react late on 19 November, another attack was launched on the Sixth Army's southern flank.

[77] In the early morning of 20 November Stavka telephoned Stalingrad Front commander Andrei Yeremenko asking if he would begin his portion of the offensive on schedule, at 08:00.

He responded he would do so only if the fog lifted; although the 51st Army opened its artillery barrage on time because front headquarters could not contact the division, the rest of the forces prepared for the operation received orders to postpone the attack until 10:00.

[80] However, confusion and lack of control caused the Soviet 4th and 13th Mechanized Corps to stumble as they began to exploit the breakthroughs achieved by the opening offensive.

[80] The 29th Panzergrenadier Division's counterattack cost the Red Army around fifty tanks, and caused Soviet commanders to worry about the safety of their left flank.

[82] However, the German division's redeployment meant that by the end of the day only the 6th Romanian Cavalry Regiment stood between advancing Soviet forces and the Don River.

[90] In the south, after a brief halt, the Soviet 4th Mechanized Corps continued its advance north, removing German defenders from several towns in the area, towards Stalingrad.

[94] German forces defending Kalach, mostly composed of maintenance and supply personnel, were not aware of the Soviet offensive until 21 November, and even then did not know in what strength the Red Army was approaching.

[97] Meanwhile, on a later date of Dec.13, the 26th Tank Corps split of southwards along the Liska river inlet in a small advance towards a bridge near the town of Nish Tschirskaya.

Such a feat was so unusual that the Stavka's own initial estimation of the encircled enemy force was only a quarter of its actual strength, because besides the fighting troops there was a huge number of extra personnel from various professions, engineer sections, Luftwaffe ground staff and others.

[109] Bridges spanning the Don River were jammed with traffic, as surviving Axis soldiers hastily made their way westwards in the cold weather, attempting to escape Soviet armor and infantry threatening to cut them off from Stalingrad.

[112] The last stragglers crossed the Don River by 24 November, and demolished the bridges to seal off the Fourth Panzer and Sixth Armies from the Soviets in Stalingrad.

[113] The Sixth Army, in the midst of chaos, began to build defensive lines, hampered by the lack of fuel, ammunition and rations, and further burdened by the advancing Russian winter.

[114] On 23 November, some German units destroyed or burned everything not necessary for a breakout operation and began to pull back towards the northern end of Stalingrad.

[115] Although German military commanders were of the opinion that Heer forces caught in the encirclement should break out, between 23 and 24 November Hitler decided instead to hold the position and attempt to resupply the Sixth Army by air.

[116] The personnel trapped in Stalingrad would require at least 680 tonnes (750 short tons) of supplies per day, a task which the depleted Luftwaffe was in no condition to carry out.

[120] The Soviet high command also began planning for Operation Saturn,[121] which was aimed at destroying the Italian Eighth Army and cutting off German forces in the Caucasus.