Following the German loss of momentum in their defeat at the Battle of the Marne, and close upon it the end of the Allies’ Great Retreat, the world came to realize that the Germans would not conquer France in one sweeping blow. The Germans, however, had realized this as early as mid-September . . . or at least their Chief of General Staff, Helmuth von Moltke, recognized this development. Both a conservative and a pessimist, Moltke had hedged all of his hope for German victory in the war upon that first great campaign, and seeing its defeat had robbed him of his fighting spirit. He had no desire to direct the German military any longer, and so Moltke resigned on September 14, 1914.
He was immediately replaced by Erich von Falkenhayn.
Falkenhayn’s first act was to clean up the wreckage of Moltke’s failed campaign. As huge numbers of German troops lay scattered across the region of the Marne River, Falkenhayn ordered them to withdraw to a position approximate with the Aise river. This would enable the German troops not only to take up a better defensive position, but also give them enough respite from the enemy to build some defenses.
As the Germans retreated, elements of the Entente forces, beginning on September 13, pursued them, hoping to stay close enough upon the German heels to force them to continue retreating. Thus, the fortunes of war had changed: just as the Germans had chased the Entente forces willy-nilly Southward across much of France, the Entente not hoped to chase the Germans aggressively enough to totally reverse the situation. The most aggressive of their elements was the British Expeditionary Force (BEF) led by John French.
French directed his British forces North over and over again, hoping to crush the defenders and therefore open a hole in the line which could then be used to flank the entire German line across Northern France. This was not to be, however, for the Germans proved quick studies to the new type of warfare demanded by the First World War. So far, their commanders had generally all learned at least two lessons so far:
1) It is easiest to take new ground by occupying the land from which your opponent has just retreated
2) A small number of adequately manned and supported machine guns can effectively nullify an attack
From September 13-27, French ordered the BEF over and again against the German defenses on the Aisne. This resulted in little more than over 13,000 British casualties. Falkenhayn had stabilized a new defensive line running (approximately) from Noyon to Verdun, acting like a massive dam to Entent forces hoping to strike Northwards.
No doubt Falkenhayn hope to eventually use this position from which to later make a stab towards Paris, but for now, there was nothing stopping him from sliding around the left flank of the Allied forces! Indeed, the Allied commanders observed the same thing: nothing was stopping them from sliding around the German right flank! Thus began a race Northwards by the opponents, each hoping to speed around the enemy’s flank before he could throw a proper line of defense across it. Indeed, one such double flanking conflict, the Battle of Picardy, had already ended on September 26 before the contest on the Aisne had been resolved.
Falkenhayn directed a masterful extension of the German lines farther and farther to the North. Meanwhile, the French (under Joseph Joffre) and British (led by John French and assisted by Douglas Haig) meant to outrace them and move East, or at the very least keep pace with the Germans in order to prevent them from moving West.
This resulted in a battle line gradually drawn almost directly North from Noyon (September 17) up to the North Sea near Nieuport, Belgium (October 16). In the meantime, several vicious battles would be fought as each army tried to gain the others’ flank. Simultaneously, the Entente and the Germans would be staking claim to French and Belgian territory from which they would hardly move over the course of the war. Thus, the move North was only later called, inappropriately, the Race to the Sea. Instead, it was a race to gain an advantage against the enemy in order to avoid a stalemate.
It was a race in which all of the competitors lost.