The Battle of Aisne: German forces successfully defend their strategic withdrawal to new lines. The Western Front now begins at the Franco-Swiss border (near Muhouse and Belfort), runs North and Northwest to Verdun, and streams West to Noyon, where the flanks of both armies lay open and unprotected though nebulous to their opponent.
The Battle of Picardy: The opponents race to extend their lines to the North, hoping to attack and gain their opponent’s flank. Neither succeeds, and both suspend their attacks when this becomes clear.
The Battle of Albert: The opponents continued the Northern extension of their lines, again hoping to do it quicker than their counterpart and thereby gain the advantage. Again, the near simultaneous movements gain nothing substantial.
October 1-4: By now the battle lines had been extended far enough North that the supreme German commander, Erich Falkenhayn, began to worry that the Entente might detach a force, swing it up North and close to the coast and thereby pass behind the German lines and relieve the besieged Belgian city of Antwerp. Falkenhayn therefore ordered the German commander in the area, Crown Prince Rupprecht, to move quickly.
Rupprecht coordinated the movement of several fast moving German units, such as the II Cavalry Corps, to guard against an Entente maneuver far to the North. In addition, Rupprecht also organized all of the reinforcements which Falkenhayn was sending him into a continued extension of the lines to the North, including an attempt to seize the city of Arras. His counterpart, French General Louis Maud’huy, however, had an advantage.
Maud’huy was empowered by his commander, Joseph Joffre, to receive troops into the area far more quickly than the Germans on account of the undamaged rail lines running through the region. Both the Germans and the French needing to take troops from elsewhere in order to extend the line to the North, but (at Arras, at least) the French were doing so much faster. When Rupprecht moved towards Arras, he found it already occupied.
Naturally, Rupprecht had to test the integrity of Arras’ defenses (there’s no sense in holding back when the enemy might simply break and run at your assault), and this contest ranged over the course of several days.
Because neither opponent wished to admit of the implausibility of gaining the advantage, both the Entente and Central forces employed attacks and counterattacks. In short, the strategic nature of the Battle could be seen as a French defense of Arras, which they had already occupied, but the Battle really represented another one of the fierce, fast moving attempts to create an opening on the enemy’s flank . . . at least two battles of this nature, Picardy and Albert, had already been fought in the steady move to the North.
The majority of the fighting had ended by October 5, which both forces admitting that the likelihood of a breakthrough was very small with respect to the need to continue extending the line North. Indeed, fighting had already shifted in that direction.
By now, the Western front looked like this: (click on the image to enlarge)