Trench mortar

After the siege of Port Arthur, where heavy artillery struggled against barbed wire and bunkers, the Germans worked with Rheinmetall from 1907 on short-barrelled mortars for their engineers. In 1914 the German army had 160 Minenwerfer, heavy 25 cm and medium 17 cm, and a light 7.58 cm model soon went into mass production. Other armies had to improvise. The Briton Wilfred Stokes designed a simple 81 mm mortar in January 1915: a bomb dropped down the barrel fired itself on a striker, and the weapon could fire 20–25 rounds a minute at ranges from about 700 metres to over a kilometre, depending on the source.

Trench mortars were light and fired from inside the trench, so they suited the destruction of machine-gun nests, wire and sniper posts at close range. Their numbers grew in every army: in 1918 the Germans had nearly 16,000 Minenwerfer, and Britain produced more than 11,000 Stokes mortars. The Compiègne armistice required Germany to hand over 3,000 trench mortars, and the Stokes design became the model for infantry mortars.