Mortars are the oldest and
most widely used artillery,
and were a critical element of trench warfare during World War I.
At the beginning of the war, the German infantry was armed with light 50mm and heavy 81mm mortars. These mortars provided the infantry critical short-range artillery support, and were a carried by every platoon. Without exception, all infantrymen were trained in their use. Over the course of the war, the lighter mortar was gradually replaced by the 81mm mortar. During the period from 1941 to 1944, Germany produced 68,000 of these weapons.
During the war, captured German 81mm mortar shells were widely used by the Red Army. They were easily fired from Soviet 82mm mortars, while shooting 82mm Soviet shells from German 81mm mortars was impossible.