Foch's General Counteroffensive, Part I
26 September to 23 October 1918
After the Allied victories during the period 8 August–16 September 1918, Ludendorff's shaken armies fell back grudgingly to the Hindenburg line. These defenses protected their lateral communications. General headquarters moved from Avesnes to Spa. The number of German divisions declined from 207 late in May to 185 by the third week in September, and German infantry battalions were reduced from four to three companies. Twenty-two divisions had to be cannibalized, and the continuing arrival of new American divisions constantly increased Foch's superiority in rifle strength. Ludendorff observed telltale signs of declining German morale. “Shirking at the front became more prevalent, especially among men returning from home leave. Overstaying of leave increased, and the fighting-line was more thinly manned.” The first quartermaster general could only plead for determined resistance to impending attacks. On 15 September, reacting to an Austrian bid for peace negotiations, he stated: “The German army … must prove to the enemy that we are not to be conquered. As we fight we must wait and see whether the enemy's intentions are honorable, in case he is ready to engage in peace negotiations this time, or whether he will again reject peace with us, or we are to purchase this peace on terms which will destroy the future of our people.” Foch feared that Ludendorff might order a retreat to the line Antwerp–Brussels–Namur–the Meuse–the Chiers–Metz–Strasbourg, shortening his front and concentrating his remaining manpower. Unremitting pressure prevented any such movement.
Foch realized that he should now attack the Hindenburg line in front of the British troops on the line Cambrai–St. Quentin–La Fere–St. Gobain, but he recognized that he also must engage the enemy elsewhere. If he advanced only in Picardy, he “ran the risk of seeing all the enemy reserves massed to meet the onslaught of our armies, and, aided by a powerful system of fortification, in a position to frustrate our efforts.” He must therefore launch a series of coordinated attacks that would immobilize the enemy forces elsewhere than in Picardy and “by their convergent directions, make them harmonize their efforts with those produced by our already successful enterprises. In short, extend the front of our offensive while keeping it always headed in the same general direction.” The employment of the American army on the right and the Belgian army on the left would create this extension. Foch's grand conception entailed