This map lays out the individual “barrage lines” and the time that artillery would fire on each line.
It was important for Officer’s to keep the men advancing “close” to this line, but back enough for safety. Each line is “labeled” A, B, C etc and their is the “firing time” on each line......A - 0 to 3 minutes, B - 3 to 6 minutes etc. Also at certain points the barrage would “hold”, firing longer, in order to allow the troops to “close up” and “consolidate” on the line before moving forward. Also, known enemy trench lines were fired on longer, to neutralize the troops in underground bunkers etc
