German General Staff (Civ6)/Civilopedia

The successes of the Prussian Army in 1870 during the Franco-Prussian War vindicated the methodical, comprehensive planning of the army, down to timetables of marching troops and railcars on tracks. Seeing a future war with France as probably inevitable, Count von Schlieffen, chief of the German General Staff, drew up plans for a future invasion of France, passing through the Low Countries and descending on Paris to the south. This invasion plan demanded a concentration of forces on the far western flank of the German army for success – but the full plan was never executed in its entirety.
With war on two fronts, the German high command transferred some of the forces intended for the heavy west flank to an entirely different battlefront (in this case, against the Russians). As the German army successfully smashed through the Low Countries, it set the French Army back on its heels as well, and a salient forming in the French lines presented the German General Staff with a tempting target. But various factors, including the reduction in forces in the Schlieffen plan, improvisational movements of German troops in response to the French, and the stiff resistance of the French and British meant that the knockout blow never achieved its goals.
The Germans had gambled and lost, and the war settled into four years of hell along the lines where the Schlieffen plan died.