A barrage is a method of delivering massed artillery fire from a few or many batteries. Individual guns or howitzers are aimed at points along one or more lines that can be from a few hundred meters to several thousand km long. The lines are usually 100 meters apart and fire is shifted from one line to the next. The guns, etc., are usually fired at a continuous steady rate using high explosive or shrapnel shells.
Barrage fire may be defensive to deny or hamper enemy passage through an area or offensive to provide covering fire that neutralizes the enemy in an area through which friendly forces are advancing. Defensive barrages are usually static (or standing or box). Offensive barrages move forward in front of the advancing troops, the pattern of barrage movement may be creeping, rolling or block. Barrage fire is normally not aimed at specific targets, it is aimed at areas in which there are known or expected targets. It contrasts with a concentration, in which the guns aim at a specific target in an area typically 150 to 250 metres diameter.
The barrage was developed by the British in their Second Boer War. It came to prominence in Terra’s World War I, notably its use by the British force sand particularly from late 1915 CE onwards when the British realised that the neutralizing effects of artillery to provide covering fire were the key to breaking into defensive positions. By late 1916 CE the creeping barrage was the standard means of deploying artillery to support an infantry attack, with the infantry following the advancing barrage as closely as possible. Its employment in this way recognized the importance of artillery fire in neutralizing, rather than destroying, the enemy. It was found that a moving barrage immediately followed by the infantry assault could be far more effective than weeks of preliminary bombardment.