The Schlieffen Plan 

'The plan was devised by Alfred von Schlieffen. It involved attacking France through Belgium in the event of war with France. The aim was to defeat France as quickly as possible. It was taken for granted that, in the event of war with both France and Russia, the really formidable adversary would be Russia and that the need to knock out France early would be overwhelmingly important. It was developed in 1905 and revised from time to time. It was also called the 'Hammer Plan'. 

It was a giant hook attack into northern France through Belgium. It was very nearly a great success in 1914 until the French defenses checked it along the Marne river. The original plan devised by Schlieffen envisaged the invasion of the Netherlands as well as Belgium. This was 'necessary' in order to achieve the 'hammer' effect. (The border between Germany and Belgium was narrow and hilly and led straight into narrow valleys in Belgium. When Helmut von Moltke took over from Schlieffen as Chief of the German General Staff he modified the plan in such a way as to avoid invading the Netherlands, as he thought that if Germany only violated Belgian neutrality there was a good chance that Britain would remain neutral. Moltke did not consult the Foreign Minister or any other politician about this assumption.'