In 1942, the Germans launched a great summer offensive in the southern USSR, whose Army Group A was tasked with capturing the vital Soviet oilfields in the Caucasus. To shield that advance into the Caucasus from Soviet armies attacking their rear with an advance southward across the Steppe and down the Volga river, the German Sixth Army, accompanied by armies from other Axis countries, was tasked with sealing off the Steppe to the north by setting up a defensive line along the narrowest stretch of Steppe, between the great bends of the Don and Volga rivers where they bulged towards each other. At the easternmost terminus of that line, on the Volga river – an important transportation artery, linking southern Russia and the Caucasus with the north – was to be interdicted at the city of Stalingrad.
The northern advance to the Volga was thus a supporting operation, whose purpose was to simply protect the rear of the German armies advancing on the Caucasus. However, when that northern advance reached Stalingrad and fought to capture that city, the symbolism of its being named after Stalin transformed the battle for its capture from a mere means to an end, and into an end in of itself, as Hitler grew increasingly fixated on seizing the city.
By late 1942, as the Germans fought desperately to wrest Stalingrad from the Soviets, who fought even more desperately to maintain a toehold in the city, the Soviet high command developed plans for an ambitious strategic counteroffensive to take advantage of the Germans’ increasing tunnel vision regarding Stalingrad, and use it to turn the tables on them. To that end, they implemented a deception plan leading up to the first step of their counteroffensive, Operation Uranus, November 19 – 23, 1942.
The German defeat came because they thought small, while their enemy thought big: the Germans thought that they were in a fight for Stalingrad as an end in of itself, while the Soviets saw the fight for Stalingrad it as but a means to a greater end. The Soviets’ ambitious counteroffensive depended upon the Germans remaining fixated on the fighting inside Stalingrad, and so played them like carnival hucksters preying on the greed of gullible marks, by carefully trickling in just enough reinforcements across the Volga to the outnumbered defenders inside the city to keep the fight going. The Germans, looking only at Stalingrad, expected that victory inside the city was within reach – at their high water mark, they occupied nearly 90% of the city, reached the Volga on multiple stretches, and split the shrinking pocket of defenders in two. All they needed was just a few more troops, and the city was theirs.
In the meantime, the Soviets quietly massed attack formations north and south of Stalingrad, facing Romanian, Hungarian, and Italian armies guarding the flanks of the Germans inside Stalingrad. On November 19th, 1942, the Soviets launched Operation Uranus with pincer attacks against the lower quality armies of Germany’s Axis partners north and south of Stalingrad, quickly smashed through and routed them, and within four days, the Soviet pincers met about 50 miles west of Stalingrad, completing a double envelopment that trapped the German Sixth Army inside that city. Desperate German efforts to reach the trapped army failed, and efforts to supply it by air fell short. Within two months, the last surviving Germans inside Stalingrad, cold, starving, and nearly out of ammunition, were forced to surrender in the first catastrophic German defeat of the war.