Western Front: First of Rickenbacker’s 26 victories; an Albatros fighter at Baussant. German aircraft losses since March 21 are 659; RAF/RFC in March and April 1,032 planes.
Flanders – Battle of the Lys ends: 13 German divisions attack at 0540 hours on 10-mile front but only capture Scherpenberg, a knoll 2 miles northwest of Mt Kemmel from French and 2-mile stretch of British-held Salient outpost line, 3 miles south of Ypres. Haig and Plumer contemplate retreat to prepared St Orner line. Ludendorff suspends the offensive at 2200 hours.
Lorraine: US codebreakers give Doughboys 1/2 hour warning of attack.
Finland:- Mannerheim captures Viborg.
Ukraine: General Groener establishes military dictatorship (Kiev martial law from April 26) under landowner Hetman (ex-Tsarist) General Skoropadski, having arrested anti-German League dissolved Rada.