The German armies in France are continuing to charge across France. But they are outrunning their lines of supply and communication. Moltke has stayed back in Luxembourg and is unable to coordinate the actions of his armies. His subordinate commanders have to make their own decisions as to which way to march. They are choosing to pursue the retreating French and British to the south east rather than swing around Paris as originally envisaged in the invasion plan.
But as the German armies lurch along, a gap opens up between the 1st Army of Kluck and the 2nd Army of Bülow. French aircraft spot the increasing isolation of Kluck’s forces. Now Joffre starts contemplating a counter-attack that could surround and destroy the 1st German army.