The Wehrmacht could have won the Battle of Stalingrad if the German 6th Army, under von Paulus, had been able to fully encircle, trap, and annihilate the Soviet 62th and 64th Armies, under Chuikov, when they were about twenty miles from the gates of Stalingrad in late August 1942. But the pinzers movement failed, leaving a gap, through which the Soviet forces managed to escape and fall back into the city, where they were able to fight a house to house battle as they were resupplied with food and ammunition from the other side of the Volga River. Although they were battle-hardened, the German soldiers of the glorious 6th Army had no experience in protracted urban warfare as they were part a field army whose men had been trained to fight only in open and extended land.
There were three reasons why Friedrich von Paulus were not able to encircle the Russian forces: 1) the German 6th Army advanced on foot as most of its divisions were standard infantry units, thus, these units were not able to move forward fast enough like mechanized or armored divisions would; 2) the 90% of German logistics ran on slow horse-drawn carts, with Wehrmacht frontline units overstretching its supply lines; 3) Friedrich von Paulus was not a frontline General but an office General, who did not act quick enough as he hesitated for two vital days, delaying the southward push of two army divisions to join the southern jaw of the pinzers, which was composed of the 4th Panzer Army’s elements.
The German advance eastward on the city of Stalingrad, which lay on the Volga River, was part of a much bigger military operation that was called in German “Fall Blau” (Case Blue), which was to be carried out by Army Group A, under Wilhelm List, and Army Group B, commanded by Maximilian von Weichs. The latter, composed of the 6th and 2nd Armies and 4th Panzer Army was to conduct the Volga campaign, capturing the city of Stalingrad, crossing the river, and establishing bridgeheads to control its boats traffics. Meanwhile Army Group A had been assigned to capture the oil fields in the Caucasus region.
Below: map that shows the uncomplete encirclement of the Red Army
Fall Blau and Battle of Stalingrad Footage