The German spring offensive, or Kaiserschlacht, also known as the Ludendorff offensive, was a series of German attacks along the Western Front during the First World War, beginning on 21 March 1918. The Germans had realised that their only remaining chance of victory was to defeat the Allies before the United States could fully deploy its resources. The German Army had gained a temporary advantage in numbers as nearly 50 divisions had been freed by the Russian withdrawal from the war with the Treaty of Brest-Litovsk.
There were four German offensives, codenamed Michael, Georgette, Gneisenau, and Blücher-Yorck. Michael was the main attack, which was intended to break through the Allied lines, outflank the British forces and defeat the British Army. Once that was achieved, it was hoped that the French would seek armistice terms. The other offensives were subsidiary to Michael and were designed to divert Allied forces from the main offensive effort on the Somme. No clear objective was established before the start of the offensives and once the operations were underway, the targets of the attacks were constantly changed according to the battlefield situation.