Quartermaster General Erich Ludendorff scheduled the beginning of Germany’s great 1918 gamble for victory on the Western Front in World War I for the first day of spring, March 21. Success depended on delivering a knockout blow before the arrival of millions of Americans in the summer. The offensive, code-named Michael, struck the sector where British and French forces joined, and matched three fresh German armies against one overstretched British army and part of another. After an intensive and carefully phased bombardment, mixing high explosive and poison gas, elite storm troops went forward. Avoiding strongpoints, they headed for the rear, leaving the mopping up to the conventional infantry. A famously thick fog aided their progress.

By the third day of the battle, the Germans had opened a fifty-mile-wide gap and were pouring into open country: Ludendorff had broken the long trench stalemate–but he had not severed the connection between the Allied armies. Now heavy losses and fatigue took their toll; hungry soldiers stopped to loot British supply dumps. After a forty-mile advance, Ludendorff’s tactical masterpiece faded to strategic inconsequence.

Meanwhile, on March 26, the desperate Allies agreed on a step they should have taken long before: putting their armies under a single commander, Ferdinand Foch. He would deftly coordinate a defense that, several times in that menacing spring, seemed on the verge of collapse. Three German “Paris guns” with a seventy-five-mile range bombarded the capital. Ludendorff launched five more offensives, all on the March 21 model: Arras (March 28), which failed; the Lys River in Flanders (April 9), which threatened to force the British back to the Channel ports; and the breakthrough at the Chemin des Dames (May 27), which reached the Marne, just forty-odd miles from Paris.

Americans helped to stop Ludendorff’s exhausted divisions at Belleau Wood and Ch[acir]teau-Thierry: he was clearly running out of time. His Oise attack (June 9) was a costly waste. Then, on July 15, Ludendorff made his final throw of the dice, seeking to pinch off Reims. This time the French turned his own defense-in-depth tactics against him, and his last offensive subsided in the chalky downlands of Champagne. Since March 21, Germany had suffered close to a million irreplaceable casualties–and the Americans were now arriving in France at the rate of 300,000 a month. For the Allies, it was the arithmetic of victory.

The Reader’s Companion to Military History. Edited by Robert Cowley and Geoffrey Parker. Copyright © 1996 by Houghton Mifflin Harcourt Publishing Company. All rights reserved.