USA: Pershing places AEF units at Foch’s disposal.
Artois – FOURTH BATTLE OF ARRAS: Ludendorffs Operation Mars fails bloodily with 9 divisions against 4 to clear northern flank of his ‘bulge’ against British Third Army and Arras itself. Local German attacks towards Amiens gain 3 miles; Germans take Hamel, Mezieres and Demuin, but fail to cut off XIX Corps’ retreat from Rosieres. At 1630 hours Rawlinson replaces Gough (recalled). French counter-attacks recapture 3 villages. Ludendorff orders completion of preparations for reduced Flanders Operation Georgette. In the estimated 8-10 days before (actually 12 days) he orders all efforts be made to secure Amiens. King visits BEF until March 30.
Western Front: Royal Flying Corps lose 58 planes in low-level operations (7 German planes shot down) dropping 40t bombs and firing 242,000 rounds.
Mesopotamia: British armoured cars capture Ana, its radio station and drive 73 miles beyond until March 29.
Atlantic: Submarine-cruiser U-157 investigates Spanish liner Infanta Isabel de Bourbon.