Western Front
Verdun: German attacks at Fort Douaumont and Malancourt.
France: British GHQ leaves St Omer for Montreuil.
Sea War
Black Sea: U33 sinks Russian hospital ship Portugal (115 lost) off Ofi near Trebizond allegedly mistaking her for a troop transport. U33 rammed by destroyer Strogiy on April 6 and forced back to Bosphorus.