It was found that a moving barrage immediately followed by the infantry assault could be far more effective than weeks of preliminary bombardment. Barrages remained in use in World War II and later, but only as one of a variety of artillery tactics made possible by improvements in predicted fire, target location and communications. The term "barrage" is widely, and technically incorrectly, used in the popular media for any artillery fire. The moving barrage was developed during the Boer War, one of several tactical innovations instituted under command of General Redvers Buller. It was a response to Boer defensive positions, notably at Tugela Heights and effective long range rifle fire. Artillery usually fired over open sights at visible targets, until the Second Boer War when indirect fire started to be used. The largest unit accustomed to firing at a single target was the brigade (i.e. an artillery battalion), normally 18 guns. Trench warfare led to the necessity for indirect firing through the use of observers, more sophisticated artillery fire plans and an increasingly scientific approach to gunnery. Gunners had to use increasingly complicated calculations to lay the guns. Individual guns were aimed so that their fall of shot was co-ordinated with others to form a pattern; in the case of a barrage, the pattern was a line. The term “barrage” was first used in World War I in English in the orders for the Battle of Neuve Chapelle in 1915. A "lifting barrage" was a development in which the barrage lifted periodically to a target further back, such as a second line of trenches. This was countered by the defenders infiltrating troops and machine guns into no-man's land or the areas between their own trench lines, so it was found necessary to comb the entire area of the advance with artillery fire. A creeping barrage (also called a moving barrage) was a barrage that lifted in small increments, usually 100 yards every few minutes, so that it moved forward slowly, keeping pace with the infantry. British normal practice evolved to fire at two lines simultaneously. Eventually, three patterns of advancing the barrage developed. In a "creeping" barrage, fire moved from one line to the next. In a "block" barrage, the 'block' moved as block to the next lines that were not previously engaged. In a "rolling" barrage, the fire on the line nearest to own troops moved to the first unengaged line furthest from own troops. By late 1917, the technique of a "creeping" barrage had been perfected and could be made to move in complex ways, with the barrage wheeling or even combing back and forth across the same ground, to catch the defenders re-emerging after the barrage had passed but it was still governed by a timetable.