Why Belgium?

In August of 1870  Germany (at that time known as the North German Confederation) invaded France. By January 1871 Germany had captured the French capital Paris and a ceasefire was soon declared, by May the war was officially over and the German army withdrew from France. The victory of this war allowed the formation of the German Empire, and an expansion of its territory (as France had to surrender some of its eastern territory to Germany), causing Germany to rise to both political and economic power in Europe. This quick victory would have a lasting effect on military thinking in Europe and particularly in Germany. Wars were to be won quickly (and thus cheaper both in money and lives) by rapid mobilization, aggressive movement and large decisive battles.

In 1905 the German military developed what would known as the Schlieffen Plan (named for one of its architects of the plan Alfred Graf von Schlieffen. The Schlieffen Plan was a the strategy that Germany would rely on in case of war with France.

The basics of the plan were that if war broke out with France, Germany would lightly defend the border with France, placing the bulk of its army on the border with Belgium. Germany would count on France attacking Germany along their mutual border.

Germany could rely on this happening for two reasons. First the lightly defended border would be a tempting target. Second France would jump at the chance to regain the territory along the Franco-German border that it lost to Germany in 1871.  The German forces defending the German border would be just enough to slow the French armies as it slowly retreated into Germany.

With the majority of the French army focused on the invading Germany, the majority of the German army would move through Belgium (either peaceably or by defeating the small Belgian army). It would cross into lightly defended northern France, rapidly moving to capture Paris, then turning south and looping around to attack from behind the French army fighting in Germany. With Paris captured and the French army surrounded and cut off from support, France would have no choice but to surrender and sue for peace.

In 1914 this plan was very appealing. France had a large army and the border of France and Germany was heavily fortified on the French side. An attack on France through the German-French border would be costly and time consuming. With Russia threatening Germany from the east, Germany could not afford a long war with France. The Schlieffen Plan offered a solution. Russian infrastructure was not nearly as developed as in France or Germany. With the lack of a large scale railroad system, Germany believed it would take Russia weeks to move enough troops to the border with Germany to pose a serious threat. German military planners believed they could use the Schlieffen Plan to quickly defeat France. Then turn all of its armies to face Russia, which Germany believed it could defeat in a one-on-one war as the German army, though smaller, was better equipped and trained.

Germany was confident that it could defeat France or Russia. What the German military planners feared was a war with France and Russia at the same time, which would stretch its armies too thin. But as France and Russia were allies they would somehow have to be fought at the same time. The Schlieffen Plan offered a strategy offered the solution to a victory over Russia and France in a single war, but it would have to deal with Belgium first.