Trench warfare
Trench warfare prevailed on the Western Front from late 1914 until the Germans launched their Spring Offensive on 21 March 1918. After the buildup of forces in 1915, the Western Front became a stalemated struggle between equals, to be decided by attrition. Frontal assaults, and their associated casualties, became inevitable because the continuous trench lines had no open flanks. Casualties of the defenders matched those of the attackers, as vast reserves were expended in costly counter-attacks or exposed to the attacker's massed artillery. There were periods in which rigid trench warfare broke down, such as during the Battle of the Somme, but the lines never moved very far. The war would be won by the side that was able to commit the last reserves to the Western Front.
Trench warfare
Enemy trenches, which would become objectives in an attack, needed to be named as well. Many were named for some observed event such as "German Officers' Trench" at Anzac or "Ration Trench" on the Somme. The British gave an alcoholic flavour to the German trenches in front of Ginchy: "Beer Trench", "Bitter Trench", "Hop Trench", "Ale Alley", and "Pilsen Trench." Other objectives were named according to their role in the trench system, such as the "Switch Trench" and "Intermediate Trench" on the Somme.