Trench warfare
The casualties caused by machine gun fire led to the widespread deployment of light machine guns such as the Lewis Gun within minor infantry units. Trench warfare also led to the rapid development of new designs of grenades, rifle grenades and light mortars—all of which represented a rapid increase in the firepower available to low-level commanders. There was a growing emphasis on field craft, especially in the British and Dominion Armies, where night-patrolling and raiding tactics soon also demanded an increase in map-reading and navigation skills. The infantryman of 1914 was content to be trained in rifle and bayonet and usually attacked in battalion formations. By 1917 he was used to grenades, rifle grenades, light machine-guns and more specialized weapons and usually worked his way forward using platoon or section tactics.