The First Battle of Cambrai was to be a single-minded battle. It was to fulfil in the simplest way the prime function of war, that is, to destroy the forces of the enemy. To attain this end it was to rely upon surprise, audacity, and rapidity of movement. Its main action was to be completed in about twenty-four hours, during which time it was proposed to penetrate the Hindenburg Line, which here consisted of four systems of trenches. Territorial gains were not to be so much considered as were the destruction and capture of enemy personnel and material. In other words, we were out to kill and chivvy Germans. The system of attack was to be one completely new for a full-dress battle. There was to be no artillery preparation whatever. To all appearance the front line was to be perfectly normal up to the very moment of attack, when two Army Corps and three Brigades of Tanks were suddenly to hurl their whole weight against the enemy. Such tactics demanded that the most complete secrecy should be maintained up to zero hour itself, and for the second time in the history of the Tanks a vital secret was successfully kept. The area to be raided lay just south of Cambrai. It was an open rolling chalk plateau, which had lain uncultivated for two years, and was now covered with a thin growth of wan grey grass. From north-west to south-east the low ridges ran, save where the dominating hump of Bourlon’s wood-crowned Hill ran across the grain of the country. On either flank of this area, sometimes at right angles to the curve of our lines, sometimes running parallel to the German lines, ran the Canal du Nord and the Canal de l’Escaut. The slopes were nowhere very steep, but the levels were everywhere varied by spurs and--so-called--“ravines.” One of these, which lay just within the German lines, and parallel to our front, for some time gave grave concern both to the Tanks and to other arms, who apparently coupled it in their minds with the Grand Cañon of Colorado. Its name sounded so formidable, and it was marked so large on the map! It might well prove a serious obstacle to the progress of Tanks. A series of exhaustive reconnaissances carried out by the Tank Corps, however, dispelled this alarming legend and the “Grand Ravine” stood revealed as being no more than a shallow dry field ditch which could be jumped by any rabbit of reasonable activity.