The arrangement of the assembly required careful planning. Seven double waves were to be assembled for the attack; there was, in consequence, little shell-proof cover in which to place the troops detailed for the capture of the later objectives. Moreover, the trenches in the forward area had been subjected to a considerable amount of artillery and trench-mortar fire, and had thus become shallow and open-mouthed, and afforded little cover to their occupants. At least two double waves had, therefore, to remain in the open for some considerable time before their turn to close up with the barrage arrived, and were in consequence liable to suffer severely from the enemy S.O.S. barrage. On the right the 6th Gordon Highlanders and 6th Seaforth Highlanders, and on the left the 9th Royal Scots and the 4th Seaforth Highlanders, led the attack. The 8th Argyll and Sutherland Highlanders, the 5th Seaforth Highlanders, the 4th Gordon Highlanders, and the 7th Argyll and Sutherland Highlanders were detailed for the attack on the farther objectives on their respective brigade areas. The 5th Gordon Highlanders from the 153rd Brigade were allotted to the 152nd Brigade as a reserve. On the extreme left of the attack the 4th Seaforth Highlanders had a small but difficult operation to perform in the first instance. The Divisional boundary on the left was the Lille Road, which crossed the enemy's trench system at the apex of a prominent salient. The 4th Seaforth Highlanders, opposite the southern shoulder of the salient, had to attack due north, while the direction of attack for the remainder of the Division was due east. The carrying out of this operation had to be so timed that the salient had been dealt with before the succeeding waves could move forward on to the attack on the German second and third lines, otherwise they would have come under enfilade fire from their left flank in the first stages of their advance. By 4 A.M. on 9th April all troops were assembled. The bombardment had continued through the previous day except during two intervals of half an hour each, which were arranged to enable the Flying Corps to photograph the results of the gun-fire. It was maintained throughout the night, and at 5.30 A.M. the attack was launched, supported by an intense artillery and machine-gun barrage. Thus began an action which developed into a true soldiers' battle, in which the Highland infantrymen fought the Bavarian for possession of the field. Perfect as the artillery barrage was, the course of events was such that in numerous instances, in all parts of the battle area, the infantry from one cause or another were unable to keep up with it, and fought out the issue with their own weapons.