Flanders: German offensive slackens 6 miles from Hazebrouck (until April 16) although Merville falls. British 5th Division arrives from Italy and 1st Australian Division comes up.
Battle of Hazebrouck (until April 15): 4 British division defend Nieppe Forest (until April 15), BEF First Army defends Hinges Ridge north of Bethune. Kaiser arrives at Armentieres, anticipating victory.
Argonne: Franco-Americans repulse attacks in Apremont Forest.
Mozambique: Action at Medo; Kartucol and Rosecol (over 155 casualties) join after former’s flanking move ambushed in swamp by Captain Kohl’s 800 Germans, 12 MGs and 1 gun; 7 hours fighting before Kohl retreats from Chirimba Hill. Rosecol resumes advance on Mwalia on April 15, skirmishes (28 casualties) with German rearguard on April 17.
Adriatic: Austrian raid on Otranto Barrage (until April 13).
North Sea: Grand Fleet base moved from Scapa Flow to Rosyth for duration of war.
Britain: Last Zeppelin raid to cross coast and cause damage or casualties. 5 Navy airships scatter 33,340lb-worth bombs across Western Midlands and Northern England (night April 12-13, 27 casualties). L-61 (Ehrlich) bombs Wigan (claims attack on Sheffield). 27 defence sorties (5 sightings) cost 3 aircraft.
Western Front: Captain H Woollett RAF in a Sopwith Camel scores 6 victories.
Flanders: Over 170 RAF planes attack at Merville junction on river Lys for 13 hours, lose 10 planes for 5 German and 5 German balloons. Little German air support for advance till April 25 but German fighters check RAF from April 13.