Von Kluck was destined to get another surprise this Sunday morning. Despite the report of his Uhlans that the British were nowhere to be seen, the astute general had placed two bodies of cavalry, about 18,000 men in all, as a precaution against a flank attack when he withdrew his men northward to meet the surprisingly strong shock of Manoury. The unsuspecting cavalry were awaiting orders to pursue either the Fifth or Sixth French armies, whichever one Von Kluck should decide to smash. They were dismounted and resting, when suddenly the western woods belched flame. The British had not fired a shot until sure of the exact range. Shrapnel poured like the blast from a furnace, men and horses fell dead in inextricable confusion. The German cavalry had no time or means to reply, and, timed to the second, the English cavalry swept down and turned the scene to a rout. In the north, despite Von Kluck's reënforcements, Manoury's army fought with great courage, at several places forcing the Germans back. But they could not cross the Ourcq against the heavy artillery. That same Sunday, Foch, in charge of the great line of reserves officially called the Ninth French Army,[19] did not attempt an advance, but rather, deliberately, allowed his line to sag. This was intended as a lure to lead the Germans on, in the hope that Manoury would be able to flank Von Kluck. But, on Sunday night, Manoury found that Von Kluck had brought back nearly all his army, and that he was being outflanked, in his turn. On Monday, reënforcements came to both sides, but more heavily to Von Kluck, who was supported by heavy masses of artillery. Manoury, lacking artillery support, held his ground, and even advanced slightly, but Von Kluck moved further on his flank. On Tuesday the Sixth Army was driven back, but fighting heavily, with all its reserves in action, Von Kluck devoting only a part of his army to the frontal attack, while one whole army corps commenced to encircle the flank. On Wednesday the disaster was almost complete. Even as late as that day Von Kluck had been able to throw in more men, released two days before by the fall of Maubeuge. Nanteuil had been taken and the army was flanked. Manoury's army was almost horseshoe shaped, with Von Kluck gathering it in as a bag is clutched by its drawstring. What would the morrow bring? The morrow brought blank astonishment. The morrow, Thursday, September 10, saw Nanteuil abandoned by the Germans and Von Kluck in full retreat. What had happened? Foch had happened! "Find out the weak point of your enemy," Foch had said once, when talking of strategy, "and deliver your blow there." "But suppose," he was asked, "that the enemy has no weak point." "Then make one!" Joffre had made the weak point and Foch had delivered the blow. It was not without knowledge of his marvelous tactical ability that the generalissimo had selected Foch for the army of reserves, for the great rebound.