In the Russian offensive against Kharkov in May their forces became
overextended and were encircled by the Germans. Here they encountered several
innovations in the system of hasty fortifications which the Germans threw up to
prevent a breakout. These defenses were built around the basic infantry
strongpoints, but the way the Germans used their combined arms and armored
equipment is revealing.
Figures 1 and 2 in the accompanying sketches outline the systems set up
by the Germans around the encircled Russian forces. The sites of the defense
areas were selected so that each island of resistance could mutually support the
ones adjacent to it.
Each island or center of resistance was formed by three concentric rings. Within
the center ring, self-propelled artillery capable of all-around fire
was emplaced. In the next outer ring, tanks were camouflaged and embedded
in the ground so that they served as pillboxes for their machine guns and other
armament. The outer ring was formed by entrenched infantry units provided
with their normal infantry weapons, including antitank guns and mortars.
Wire entanglements were laid between the embedded vehicles of the
second ring and along the channels of fire of the infantry weapons. Clever
signaling devices such as cowbells and self-igniting firecrackers were hung on
the wires and nearby bushes to warn of an enemy approach at night.
In the gaps between centers of resistance, minefields were laid and
charted, and high-trajectory weapons laid to cover defiladed areas.
Outside this system of defensive areas which encircled the Russian
troops, mobile combat teams were located, ready to rush to any part of the
circumference that might be threatened either from within or without.