The Sixth Army was being bled white amidst the ruins. The rifle strength of whole companies was often reduced to little more than a squad in an attempt to take a single house. The battle lines were now drawn through the hallways of individual buildings rather than by street or city blocks. The Germans decided to bring in fresh specialized units for the final assault; five battalions of elite pioneers specially trained in street fighting and veterans of the bitter street battles of Voronezh were summoned to take the last stubborn outposts between the machine shops of the Barrikady Gun Factory and the Volga. However, the pioneers of Major Rettenmaier had never seen a battle the equal of that for the “Commissar’s House”.