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.