Operation Blücher-Yorck was planned primarily by General Erich Ludendorff, the First Quartermaster-General of the German Army, who was certain that success at the Aisne would lead the German armies to within striking distance of Paris. Ludendorff, who saw the British Expeditionary Force as the main threat, believed that this, in turn, would cause the Allies to move forces from Flanders to help defend the French capital, allowing the Germans to continue their planned Flanders offensive ("Hagen") with greater ease. Thus, the Aisne drive was to be essentially a large diversionary attack.