[1][2]A German barrage falling on Allied trenches at Ypres, probably during the second battle in 1915.A barrage is a line or barrier of exploding artillery shells, created by the co-ordinated aiming of a large number of guns firing continuously. Its purpose is to deny or hamper enemy passage through the line of the barrage, to attack a linear position such as a line of trenches or (as a creeping or rolling barrage) to neutralize the enemy in the path of an advance by friendly troops. It contrasts with a concentration, in which all the guns aim at the same small area.