Eingreif division is a term for a type of German Army formation of World War I, which developed in 1917, which was responsible for engaging in immediate counter-attacks against enemy troops who broke through a defensive position being held by a "front-holding" division (Stellungsdivision). Attacks by the French and British armies against the Westheer on the Western Front had been met in 1915 and 1916 by increasing the number and sophistication of trench networks, the original improvised defences of 1914 giving way to a centrally-planned system of trenches in a trench-position and then increasing numbers of trench-positions, to absorb the growing firepower and offensive sophistication of the Entente armies.