Château-Thierry was thus the peak of the German push—the apex of the triangle pointing toward Paris. The enemy supplied its forces in this peak principally by the road that ran southward from Soissons and touched the Marne at Château-Thierry. To the west of this road and just south of the city of Soissons, is the forest of Villers-Cotterets. The enemy occupied the northern and eastern limits of the forest and the remainder of it was in the hands of the French.
This forest has always been considered one of the sentinels of Paris. It was located on the right flank of the German salient. It was a menace to that flank, and offered a most attractive opportunity for an Allied counter offensive from that direction. The Germans were not unmindful of this.
The enemy knew that in the forest of Villers-Cotterets it would be possible for Marshal Foch to mobilise his much-feared reserves by taking advantage of the natural screen provided by the forest. That Foch reserve still remained a matter for enemy consideration in spite of the fact that the successive German offensive since March 21st had met with considerable success with regard to the acquisition of territory. The Germans, however, had been unable to ascertain whether Foch had been forced to bring his reserves into the fight.
The situation demanded a full realisation by the enemy of the possible use of this reserve at any time and they knew that their lines in Villers-Cotterets Forest offered an ever present invitation for the sudden application of this reserve strength. Their lines at that point were necessarily weak by the superiority of the Allied position and, as a consequence, the Germans guarded this weak spot by holding in reserve behind the line a number of divisions of the Prussian Guard.
For the same reason, the enemy maintained constant observation of the French position. Their planes would fly over the forest every day taking photographs. They sought to discover any evidences indicating that Foch might be preparing to strike a blow from that place. They made careful note of the traffic along the roads through the forest. They maintained a careful watch to ascertain whether new ammunition dumps were being concealed under the trees. Their observers tried to ascertain whether any additional hospital arrangements had been made by the French at that point. Any of these things would have indicated that the French were preparing to strike through the forest but the Germans found nothing to support their suspicions.
Nevertheless, they maintained their lines at maximum strength. A belief existed among the German High Command that an attack might be made on July 4th, out of consideration to American sentiment. When the attack did not develop on that day, they then thought that the French might possibly spring the blow on July 14th, in celebration of their own national fête day. And again they were disappointed in their surmises.
This protracted delay of an impending blow worried the enemy. The Germans realised full well that they were fighting against time. Their faith in the capacity of their submarines to prevent American strength from reaching the line, had been abandoned. They now knew that every day that passed meant just that many more American soldiers arriving in France, and the consequent strengthening of the Allied forces during a season when the Germans, through their repeated offensives, were suffering terrible losses and were consequently growing weaker.
So, on July 14th, when the Allied counter-offensive had still failed to materialise, the German forces, by the necessity for time, moved to a sudden and faulty decision. They convinced themselves that they had overestimated the Allied strength. They accepted the belief that the reason Foch had not attacked was because he did not have sufficient strength to attack. With this, then, as a basis for their plans, they immediately launched another offensive, hoping that this might be the one in which they could deliver the final blow.
This action began on Monday morning, July 15th, and extended from Château-Thierry eastward along the valley of the Maine, northward to Rheims and thence eastward. By a remarkable coup, one small patrol of French and Americans deprived the enemy of the element of surprise in the attack. On the morning of the previous day, this patrol successfully raided the enemy lines to the east of Rheims and brought back prisoners from whom it was learned that the Germans intended striking on the following morning. The objectives of the offensive were the French cities of Épernay and Châlons. The accomplishment of this effort would have placed the Rheims salient in the hands of the enemy and brought the German lines southward to positions straddling the Marne, down the valley of which they would thus be able to launch another offensive on a straight road to Paris.
The Germans needed considerable strength for this new effort. To muster the shock divisions necessary for the attack, they had to weaken their lines elsewhere. The first reserves that they drew for this offensive were the Prussian Guard divisions which they had been holding in readiness in back of the weak spot in their line in the Villers-Cotterets Forest. Those divisions were hurriedly transported across the base of the V-shaped salient and thrown into the attack to the east and the southwest of Rheims.