A blitzkrieg is a military tactic that is used to create psychological shock and disorganization in enemy forces through the employment of surprise, speed, and superior firepower. This sudden warfare is designed to force the enemy into a quick surrender. Blitzkrieg is a German word meaning “lightning war.”

A blitzkrieg does not aim to physically overcome an enemy. Instead, the purpose of a blitzkrieg is to use ease of movement, shock, and locally concentrated firepower in a skillfully coordinated attack to paralyze the enemy’s ability to coordinate his own defenses. The enemy’s paralysis is then exploited by penetrating to his rear areas and disrupting his whole system of communications and administration.

The blitzkrieg was first tested by the Germans during the Spanish Civil War in 1938 and against Poland in 1939. The Germans used combat groups consisting of tanks, dive-bombers, and motorized artillery to split the enemy’s forces and to disrupt the main enemy battle position at the point of attack. Wide sweeps by armored vehicles followed, creating large pockets of trapped and immobilized enemy forces. These tactics reduced the number of deaths and equipment losses for both sides because of the speed and short duration of the campaign.

Blitzkrieg tactics were used in the successful German invasions of Belgium, the Netherlands, and France in 1940. They were used by the German commander Erwin Rommel during the desert campaigns in North Africa and by U.S. General George Patton in the European operations of 1944. 

Fighting in Stalingrad itself could not have been more different. It represented a new form of warfare, concentrated in the ruins of civilian life. The detritus of war - burnt-out tanks, shell cases, signal wire and grenade boxes - was mixed with the wreckage of family homes - iron bedsteads, lamps and household  utensils. Vasily Grossman wrote of the 'fighting in the brick-strewn, half-demolished rooms and corridors' of apartment blocks, where there might still be a vase of withered flowers, or a boys homework open on  the table. In an observation post, high in a ruined building, an artillery spotter with a periscope might watch for targets through a convenient shell-hole in the wall, seated on a kitchen chair. 

German infantrymen loathed house-to-house fighting. They found such close-quarter combat, which broke conventional military boundaries and dimensions, psychologically disorientating. During the last phase of the September battles, both sides had struggled to take a large brick warehouse on the Volga bank, near the mouth of the Tsaritsa, which had four floors on the river side and three on the landward. At one point, it was 'like a layered cake' with Germans on the top floor, Russians below them, and more  Germans underneath them. Often an enemy was unrecognizable, with every uniform impregnated by the same dun-coloured dust.

German generals do not seem to have imagined what awaited their divisions in the ruined city. They lost their great Blitzkrieg advantages and were in many ways thrown back to First World War techniques... In its way, the fighting in Stalingrad was even more terrifying than the impersonal slaughter at Verdun. The close-quarter combat in ruined buildings, bunkers, cellars and sewers was soon dubbed 'Rattenkrieg' by German soldiers. It possessed a savage intimacy which appalled their generals, who felt that they were rapidly losing control over events. 'The enemy is invisible,' wrote General Strecker to a friend. 'Ambushes out of basements, wall remnants, hidden bunkers and factory ruins produce casualties among our troops.' 

Much of the fighting consisted not of major attacks, but of relentless, lethal little conflicts. The battle was fought by assault squads, generally six or eight strong, from 'the Stalingrad Academy of Street Fighting'. They armed themselves with knives and sharpened spades for silent killing, as well as submachine-guns and grenades. (Spades were in such short supply, that men carved their names in the handle and slept with their head on the blade to make sure that nobody stole it.) The assault squads sent into the sewers were strengthened with flame-throwers and sappers bringing explosive charges.