"...Joffre made his mark almost immediately upon his appointment as Chief of Staff in the spring of 1911. The staff-level war games of that year were hailed internally as a tremendous success making use of his predecessor's revision of mobilization plans and corps-level reorganization; they incorporated "escalating scenarios" in which France went to war exclusively against individual states all the way up to a general war including every state in Europe including the British Empire. The focii of the games, however, were on the longstanding assumptions in Paris about what "the next war" - one can interpret how one likes the self-fulfilling prophecy of treating such a conflict as an inevitability - would look like, and this was as a limited conflict between France and Austria on one side and Germany and Italy on the other. That these alliance systems that had informally stood in place since the early 1870s were, ironically, at a nadir in 1911 was besides the point; French military leaders from Joffre on down presumed that unless France was fighting a limited conflict that these "natural alliances" would be triggered.
The games helped the French General Staff developed what became known as War Plan III, or the Joffre Plan, and here Joffre's impact on the actual conflict when it did "inevitably" break out are plain. It is remarkable, with hindsight, how much the contours of the Joffre Plan resemble what actually occurred when the Central European War in fact did occur less than a decade after its design. Variant III-B and all others presumed a French transit of Belgium as one of its three offensive prongs into western Germany; Variant III-D presumed Denmark honoring its treaty commitments to the "Iron Triangle" (a name long since disused, but whose basic alignment remained) and being overrun in four days, but tying down enough German divisions to allow the French offensives to work. The plan called for the total mobilization of France's entire 110 divisions at once - the largest land army in Europe and probably the world - and to launch three offensives into Germany and one into Italy's Piedmont. The biggest offensive was to be through Belgium, which France's assumption in III-B and III-D treated as a neutral and in III-C as a co-combatant, with a full fifty divisions marching through the "Limburg salient" south of Maastricht to strike at Aachen and then breakthrough into the Rhineland; fifteen divisions apiece were to launch an attack against the Trier Triangle (but primarily Saarbrucken, regarded as the weak link and to draw German forces south from the "Northern Gibraltar" of Luxemburg) and from Alsace toward Karlsruhe and the Upper Rhine Valley, thus seizing the initiative on both sides of the Vosges. The remaining thirty divisions of French forces would attack from bases in Grenoble through the high pass of Valloire into Italy. Germany and Italy would be unable to maintain full strength on both of these fronts thanks to the Austrian threat, with Joffre presuming at least sixty German divisions forced to deploy to the Inn River and two dozen more sent to Silesia and the Bohemian mountain passes, the majority of the Italian Army dispatched to the Gorizia Hills and Trentino, and both enemies struggling to fight a two-front war against two advanced opponents.
Aachen was the key to the Joffre Plan, though. The Ardennes made for a difficult territory to attack across but was certainly easier than the neighboring Eifel Plateau, and thrusting through the lowlands that opened up to the Rhine-Ruhr and the North German Plain was key. It was here that a number of officers expressed skepticism at some of Joffre's estimates, particularly those regarding an Alpine offensive to seize the Piedmont; a number of them, once Joffre was more ensconced in his position, were infamously dismissed for "defeatism." The Hindenburg Line that defended the Luxemburg-Saarbrucken salient to Joffre may as well not have existed, nor the smaller but still formidable border fortifications near Alsace; the logistics of Alpine warfare and breaking through such difficult terrain was a matter merely for elan to solve. Joffre's most optimistic Variant III-C, in which the Belgian Army struck into Aachen and northern Luxemburg from their bases in Liege and the critical crossroads of Bastogne, suggested French armies would occupy most of the Piedmont, including Turin, within 28 days and that Cologne would fall with French armies "on the Rhine" within 35. These estimates were, to say the least, wildly optimistic, even with more modest assumptions about Austria's "defensive front" in the east, and also assumed that once French armies had taken Cologne and thus threatened the Ruhr and Germany's ability to resupply Luxemburg, Berlin would sue for peace.
The Joffre Plan became the backbone of French war planning for the remainder of the 1910s, then, with new variants, mobilization tables and equipment provisions designed entirely to satisfy it. Joffre's penchant for sacking or reassigning officers who told him what he did not want to hear became more infamous, and after the war, when the failure of the Joffre Plan became more clear, only added to his ignonimy..."
- The Central European War