At the close of 1915 the first serious effort to obtain unity of action between the Allies was made, and a conference of the leaders of the French, British, Belgian and Italian armies, with representatives present from the Russian and Japanese, was held at Joffre's headquarters in December. As a result they adopted the principle of a simultaneous general offensive in 1916 by France, Britain, Russia and Italy. In view of the rawness of the British troops, it was recognized that time must he allowed for training, and that the offensive could not begin before the summer of 1916, although it was hoped to carry out preliminary attacks to wear down the enemy's strength.
But German action was to dislocate this scheme, and only the British share came fully into operation, and not even that into full effect. Falkenhayn was about to fulfil his long-cherished plan for a Western offensive, hut with characteristic limitations. Always a believer in the strategy of attrition, he now carried this ruling idea into tactics, and produced the new form of attack by methodical stages, each with a limited objective. In a memo randum to the German emperor at Christmas 1915 he argued that England was the staple of the enemy alliance. "The history of the English wars against the Netherlands, Spain, France and Napoleon is being repeated. Germany can expect no mercy from this enemy, so long as he still retains the slightest hope of achieving his object." Save by submarine warfare, however, Eng land and her army were out of reach, for their sector of the front did not lend itself to offensive operations. "In view of our feel ings for our arch-enemy in the war that is certainly distressing, but it can be endured if we realize that for England the campaign on the Continent . . . is at bottom a side-show. Her real wea pons here are the French, Russian and Italian armies." He re garded Russia as already paralysed, and Italy's military achieve ments as unlikely to affect the situation. "Only France remains. France has almost arrived at the end of her military effort. If her people can be made to understand clearly that in a military sense they have nothing more to hope for, breaking-point would be reached, and England's best sword knocked out of her hand." He added that a break-through in mass was unnecessary, and that instead the Germans should aim to bleed France to death by choosing a point of attack "for the retention of which the French command would be compelled to throw in every man they have." Such objectives were either Belfort or Verdun, and Verdun was chosen, because it was a menace to the main Ger man communications, because it offered a salient and so cramped the defender, and because of the moral effect if so renowned a place was lost to France.
The keynote of the tactical plan was a continuous series of limited advances which by their menace should draw the French reserves into the mincing-machine of the German artillery. And each of these advances was itself to be secured from loss by an intense artillery bombardment, brief for surprise and making up for its short duration by the number of batteries and their rapid ity of fire. By this means the objective would be taken and con solidated before the enemy could move up his reserves for counter-attack. Although the French Intelligence branch at gen eral headquarters gave early warning of the German preparations, the Operations branch were so full of their own offensive schemes that the warning fell on deaf ears. Further, the easy fall of the Belgian and Russian fortresses had led to a commonly held view that fortresses were obsolete, and Joffre, persuading the French Government to "declass" Verdun as a fortress, had denuded it of guns and troops. The forts were only used as shelters and the trench lines which took their place were inadequate and in poor repair. Yet in the outcome eight months' bombardment was to leave the forts almost undamaged! At 7.15 A.M. on Feb. 21, the German bombardment began, on a front of 15 m., and progressively trenches and wire were flat tened out or upheaved in a chaos of tumbled earth, giving to the countryside a weird resemblance to the surface of the moon. At 4.45 P.M. the German infantry advanced, although the first day only on a 21 m. front. From then until Feb. 24 the de fenders' line east of the Meuse was crumbled away as by the erosion of the tide.
"Operations" still argued that it was only a feint, but Joffre decided to send de Castelnau to discover the true situation and with full powers to act. De Castelnau swung back the right flank but ordered the line of the forts to be held at all costs and entrusted the defence to Petain, for whose use a reserve army was assembled. Petain's first problem was not so much de fence as supply—the German heavy guns had closed all avenues into the salient except one light railway and the Bar-le-Duc road. While gangs of territorial troops worked night and day to keep this in repair and widen it, Petain organized the front into sectors and threw in repeated counter-attacks, which, helped by the narrowness of the front, at least slowed down the advance. Falkenhayn sought, somewhat late, to widen the front, and on March 6 the Germans extended the attack to the west bank of the Meuse. But the defence was now stiffening, the numbers balanced, and the immediate thrust to Verdun was checked.