Western Front: Immelmann and Boelcke first German airmen (8 air victories each) to receive Pour le Merite.
Gallipoli: Turco-German Fokker Es (3 recently arrived) shoot down a second RNAS aircraft off Helles (first previous day); last Allied air casualty of campaign in which British dropped 1,155 bombs weighing total 27t.
Argonne: German gas attack in Forges sector between river Meuse and the Argonne.
Austro-Montenegrin armistice (until January 20), broken off.
Germany: Liebknecht expelled from SPD in Reichstag.
Canada: Parliament votes for $250m war credit and 25% profits tax (debate until May 18).