The attack of the 36th Division, of which the final objective was from Lumm Farm to a cutting on the Wytschaete-Oosttaverne Road east of Staenyzer Cabaret, was to be made by two Brigades, the 107th on the right and the 109th on the left, each having one battalion from the 108th Brigade attached. Each Brigade was to attack with two battalions in front, which advanced as far as the Blue Line, the ground in rear of that objective being "mopped up" by the attached battalion of the 108th Brigade. The remaining two battalions of each Brigade were to pass through on the Blue Line for the advance to the Black, providing their own "mopping-up" parties. The 107th Brigade was to use the 8th Rifles on the right and the 9th on the left for the attack on the Blue Line, with the 15th and 10th Rifles to pass through to the Black Line. The 12th Rifles, from the 108th Brigade, carried out the work of "mopping up" and consolidation in rear. The 109th Brigade was to use the 14th Rifles on the right and the 11th Inniskillings on the left to take the Blue Line, and the 10th and 9th Inniskillings to take the Black Line. The 11th Rifles were attached for consolidation and "mopping up." The boundary line between the 36th and 16th Divisions ran, it will be noticed, along the main street of Wytschaete, half the village being in the objective of each Division. The date of the attack was designated "Z" day, the five days of preliminary bombardment being designated "U," "V," "W," "X," and "Y." There had been considerable bombardment of the ridge before "U" day, but from this day onwards it became more intense. Its object was not the total destruction of the hostile trench system, but the disorganization of the defence by the smashing of concrete emplacements and shelters. It took nothing short of an 8-inch howitzer to destroy the German concrete, while 12-inch and 15-inch howitzers fired on Wytschaete. The cutting of wire was performed by the 18-pounders, assisted in the case of the front line by trench mortars. Further to disorganize the enemy, a programme of barraging night and day his communications, and shelling his billets, was carried out, while bursts of fire with lethal and lachrymatory gas shell of various sorts took place throughout the period. Special half-hour hurricane bombardments of Messines and Wytschaete, during which every gun available, from largest to smallest, was in action, were carried out. The barrage for the advance consisted of, firstly, a creeping barrage of 18-pounder shrapnel, moving in advance of the infantry, with average lifts of a hundred yards, at the rate of a hundred yards in three minutes; and, secondly, a standing barrage of 18-pounders, 4.5 inch howitzers, and medium and heavy howitzers, established in succession on trenches and strong points. For the creeping barrage there was one gun to twenty yards, firing at maximum rate. One gun a section fired smoke shell, to screen the infantry.