On the night of November 17th-18th, the two leading Brigades of the 62nd Division took up their battle front; the 185th on the right, and the 187th on the left. Detachments of the 36th Division were kept in the outpost line, so as to avoid any chance of the enemy spotting the relief; and, though he rushed one of these posts, and captured two men of the 36th, he was not made aware of the date or time of the attack, or of the fact that Tanks were to be used. These lumbered off from the advanced Tankodrome at the south-west corner of Havrincourt Wood, and reached their lying-up places by midnight on Y Z night, November 19th-20th. The pace of the Tanks was calculated, after practical experience, at a hundred yards in five minutes, and the Artillery barrage and Infantry advance were regulated accordingly. The two leading Infantry Brigades were to attack on a two-Battalion front, preceded by twenty-two Tanks. The remaining two Battalions of each Brigade, preceded by eight Tanks, were to leap-frog through the leading Battalions, picking up all surviving Tanks on their way. Second only, if second, to the Tanks in novelty and effectiveness was the new, great weapon of surprise, perfected by the lessons of a hundred mistakes. We may quote the evidence of a contemporary Battalion diarist, who ascribed the initial success, first, to the Tanks (‘these dealt extremely effectively with the enemy wire, which was very formidable in places’), and, secondly, to secrecy (‘even in the marches up to the line the destination of the Battalion for that night was not made known to anybody below the rank of an Officer. That this policy paid well may be judged from the fact that the enemy was obviously taken completely by surprise’). This record, taken from the account of the 2/4th York and Lancasters, is repeated in almost every diary. In order to keep the secret, very elaborate precautions had been taken. Aerial photographers were deceived by marches on the off-side of roads. Lorries going northward carried lights, lorries going southward carried none. No fires were allowed. There was no preliminary bombardment, and, as indicated above, no one in the Division knew the destination of the Division. Zero hour on November 20th was 6-20 a.m., and at 6-20, on that foggy morning, the first intimation to the Germans of the 62nd Division’s attack was the sight of a sheet of flame from every gun, and of heavy Tanks looming through the mist. No wonder, that the first bound of the eager Infantry started with conspicuous success, and was attended by comparatively few casualties.