Guns were massed against the position picked out for assault. They were massed without being seen. The present day gunner does not trust to the eye. He uses his gun with mathematical precision. This system the French artillerists had reduced to an exact science. At a given time these guns opened at the same instant, and on a preconcerted plan swept the position with a squall of fire. In this tornado everything, entanglements and obstructions, were cut to pieces; trenches crumbled; concrete redoubts were split into ruins. Amid the hurricane of lead nothing could live. Having swept the position the guns drew a curtain of fire behind it while the infantry advanced to the attack. More than once it happened that the French infantry charged up to and captured trenches after this treatment without losing a man. None were left to oppose them. In fact, however, no assaults were made until the "lie" of the enemy's trenches and defences was thoroughly known. The first German "tooth" drawn under this system was their fortification on the spur at Vermelles, four miles to the south of La Bassee. That was on December 7. After that fangs were one by one extracted all round the hostile front.[15] [15] Other examples are the Spur at Notre Dame de Lorette near Arras; the ridge north of Beausejour in Champagne; the Crete de Combres at Les Eparges on the Meuse; the Bois de Pietre on the Moselle; and Hartmannsweilerkopf in Alsace. One of these fangs was the German position on the spur at La Bassee. Along the south side of this spur early in February the Irish Guards and the Coldstreams turned the enemy out of his defences among the brick stacks there, and made the position useless to him save for purposes of defence. Affairs having reached this stage the plan of assault was decided upon by Sir John French on February 19. It was to be carried out by the British First Army, under the command of Gen. Sir Douglas Haig, with the support of a large force of heavy artillery, a division of cavalry and some infantry of the general reserve. The attack was to be directed against Neuve Chapelle. Holding attacks, that is practically feints, were to be made at the same time by the Second Army against La Bassee from the south and by the 4th Army Corps and the Indian Army Corps to the north. The German position at La Bassee formed a buttress of the line which they had been striving to draw across the valley of the Lys. Their line from La Bassee across the flats of the valley as far as the hills south of Ypres had become a maze of diggings and entanglements, and was deemed to be impregnable. It was important to break this barrier. For five months at enormous cost the enemy had fought to build it up and to maintain it.