The thing with the Schlieffen plan was that as soon as day one began it could not be stopped because day one was mobilisation so from then on it was like a steamroller. The first stage of the Schlieffen plan after mobilising was to launch an attack on the French border using only a around 120,000 men, this was nothing more than a dummy attack, used to draw the French forces to defend their border, Schlieffen knew they would do this from past experience, they had done it in the Franco – Prussian war of 1870 and they would do it again.
Once the French had been drawn to the border the Germans marched an army of one million men through Belgium, this is where the bulk of the German attack was going to come from, they were going to march through Belgium and into France, sweeping around the capital as they did and en circling it. This would then catch the French in the middle of the two German forces and was described as a hammer hitting a blacksmiths anvil, the sweep through Belgium through France and around Paris acting as the hammer crushing the French into the German forces on the border, acting as the anvil.
This is the stroke of genius though; Schlieffen was going to take Britain out of the war before they had time to even get there. As the German’s advanced through Belgium and then France they were to capture the ports as they went. By doing this, Britain can’t get any troops even to the fight and meaning they could not influence the war!
So precise was the Schlieffen plan that they had it timed so that it would finish in exactly 40 days and also that it would run in time with the German train timetable, allowing the forces to get to the eastern border hassle free.
Had it not been for harder resistance in Belgium and the deep concrete forces protecting cities and the fact that the Russians mobilised within 4 weeks and not 8, the Schlieffen plan would have worked perfectly. Because the Germans were held up in Belgium, it gave the British Expeditionary force enough time to land an army of 125,000 men in France, who ran into the Germans and Mons and inflicted severe casualties on them, not only did they do this, they also through the Germans off course, meaning they did not encircle Paris and the French attacked the Germans exposed right flank, leading to the stalemate of the war on the western front.