The Schlieffen Plan
The Schlieffen Plan (German: Schlieffen-Plan, pronounced [ʃliːfən plaːn]) was a 1905 German General Staff thought-experiment which later became a deployment-plan and set of recommendations for German Commanders to implement using their own initiative. It was adopted as Deployment Plan Aufmarsch I in 1905 (later Aufmarsch I West) and modelled a Franco-German war, which would not involve Russia but was expected to include Italy and Austria-Hungary as German allies. "[Schlieffen] did not think that the French would necessarily adopt a defensive strategy" in such a war, even though their troops would be outnumbered "but he recognized that this would be their best option and it therefore became the central theme of his analysis." In Aufmarsch I, it was stated that Germany would have to go on the offensive to win this kind of war, which entailed all of the German army being deployed on the German–Belgian border, so it could launch an offensive into France, through the southern Dutch province of Limburg, Belgium, and Luxembourg. The deployment plan assumed that Italian and Austro-Hungarian troops would defend Alsace-Lorraine.
The French General Staff Plan XVII and the German Aufmarsch I were just deployment plans and not operational plans, though both were designed with specific operations/campaigns in mind. The operations that followed from the German General Staff deployment plans, including Aufmarsch I, had no set durations or timetables because it was assumed that the timing of the operations would be decided by Army-level Commanders (each commanding c. 100,000 combat troops), carrying out the overall plans under their own initiative. Schlieffen thought that the offensive operation following from Aufmarsch I, could force the smaller French Army to commit itself to a decisive battle in which much of it might be destroyed, for fear of the German army breaching their 'second defensive area' (the river Marne and the fortress-sectors of Verdun and Paris). If the French Army was defeated in battle, it would be weakened but if it denied battle, the defensive value of the 'second defensive area' could be greatly reduced. Building on this decisive first operation/campaign, further operations/campaigns would eventually bring about the defeat of France.
Helmuth von Moltke the Younger succeeded Schlieffen in 1906 and became convinced that an isolated Franco-German war was impossible, due to shows of Franco-Russian solidarity during the Moroccan and Bosnian crises. Moltke also became convinced that Italy would not join in, due to the increasing Italian-Habsburg enmity and the anticipation of British entry into a Franco-German war, in which the Italian economy would be highly vulnerable to blockade. Under Moltke, Aufmarsch I was retired but in 1914 he attempted to apply the offensive strategy of Aufmarsch I West, to the deployment plan Aufmarsch II West. This plan was designed for a two-front war and so reduced the forces available in the west by a fifth, meaning that the German offensive was too weak to succeed.
The French General Staff Plan XVII and the German Aufmarsch I were just deployment plans and not operational plans, though both were designed with specific operations/campaigns in mind. The operations that followed from the German General Staff deployment plans, including Aufmarsch I, had no set durations or timetables because it was assumed that the timing of the operations would be decided by Army-level Commanders (each commanding c. 100,000 combat troops), carrying out the overall plans under their own initiative. Schlieffen thought that the offensive operation following from Aufmarsch I, could force the smaller French Army to commit itself to a decisive battle in which much of it might be destroyed, for fear of the German army breaching their 'second defensive area' (the river Marne and the fortress-sectors of Verdun and Paris). If the French Army was defeated in battle, it would be weakened but if it denied battle, the defensive value of the 'second defensive area' could be greatly reduced. Building on this decisive first operation/campaign, further operations/campaigns would eventually bring about the defeat of France.
Helmuth von Moltke the Younger succeeded Schlieffen in 1906 and became convinced that an isolated Franco-German war was impossible, due to shows of Franco-Russian solidarity during the Moroccan and Bosnian crises. Moltke also became convinced that Italy would not join in, due to the increasing Italian-Habsburg enmity and the anticipation of British entry into a Franco-German war, in which the Italian economy would be highly vulnerable to blockade. Under Moltke, Aufmarsch I was retired but in 1914 he attempted to apply the offensive strategy of Aufmarsch I West, to the deployment plan Aufmarsch II West. This plan was designed for a two-front war and so reduced the forces available in the west by a fifth, meaning that the German offensive was too weak to succeed.