The affair might be a surprise for an enemy whom our pressure on the Salient had forced to withdraw a large number of troops from the Somme front. If the tanks worked well, it ought to result in the breaking through of the triple-trench system of the Hindenburg Line, which had been immensely strengthened by the Germans since their leisurely retirement thither in April. We might expect to push on across their reserve system three or four miles behind the Hindenburg Line. We might even capture Cambrai twelve thousand yards from our jumping-off place, though that would be a side-issue; but, with luck, our attack would win us more high ground towards the north and the north-east, whence we could later strike in whichever direction seemed most profitable. Secrecy and hard-hitting would be of the essence of the contract, since the enemy could bring up reinforcements in a couple of days. Meantime the Guards Division would stand by at two hours’ notice, ready to be used as required. If Cambrai were taken, they would be called upon to hold it and make good. If it were not, then the battle would rank as a raid on a big scale, and the Division might be used for anything that developed. That same day Major Baggallay, M.C., carried out a road reconnaissance of the front at Doignies and Demicourt north of Havrincourt Wood. The situation there betrayed nothing. “Apparently the whole of that front-sector was habitually very quiet.” Twenty-four hours later, it was alive and roaring with our tanks rooting through the massed wire of the Hindenburg Line, the clamour of half-a-dozen divisions launched at their heels and the smashing fire of our guns in advance of them and their covering smoke-screens; while far to the north and south dummy attacks, gas and artillery demonstrations veiled and confused either flank. The opening day was, beyond doubt, a success. The German line went out under the tanks, as breakwaters go out under the race of a tide; and from Gonnelieu to north of Hermies three systems of their defence were overrun to a depth of four or five miles. By the 21st November our attack had punched out a square-headed salient, ten miles across the base, the southerly side of which ran along the high ground of the Bonavis Ridge, more or less parallel to the St. Quentin-Escaut Canal from Gonnelieu to Masnières, which latter place we held. The easterly side lay from Masnières through Noyelles-sur-l’Escaut and Cantaing to Fontaine-Notre-Dame and Bourlon Wood. This latter, as the highest point of command, was the key of the position on our north flank. Thence, the northerly flank of the salient ran roughly westward from the wood, south of Mœuvres till it joined our original front north of Boursies. About one half of the salient was commanded by German guns from the north of Bourlon Wood, and the other half from the south in the direction of the Bonavis Ridge.