Description Somme Defensive, 21 March - 6 April 1918. The German high command decided to attack on the British-held Somme front in the direction of Amiens. A breakthrough at this point would separate the French from the British, push the latter into a pocket in Flanders, and open the way to the Channel ports.
The offensive began on 21 March 1918 with three German armies (about 62 divisions in all) in the assault. British defense lines were pierced in rapid succession. By 26 March Amiens was seriously threatened, and on the following day a gap was created between the French and British armies. But the Germans lacked reserves to exploit their initial phenomenal successes, and the Allies moved in enough reserves to bring the offensive to a halt by 6 April. The Germans had advanced up to 40 miles, had captured 1,500 square miles of ground and 70,000 prisoners, and had inflicted some 200,000 casualties. They had failed, however, to achieve any or their strategic objectives; destruction of the British, disruption of Allied lateral communicational and capture of Amiens.
On 25 March 1918, at the height at the German drive, Pershing placed the four American divisions at that time ready for combat at the disposal of the French. But only a few American units were engaged. They included the 6th, 12th, and 14th Engineers and the 17th, 22d, and 148th Aero Squadrons, a total of about 2200 men.