South of Ypres, British and ANZAC forces have seized Messines Ridge, after first exploding mines under German positions. German counter-attacks have failed to recapture lost ground. Now the Germans begin to withdraw to prepared positions to the east, fearing that the British will launch
further attacks to exploit their success.
In fact the British do not have the men in place to push on from Messines. Haig sees this battle as merely a prelude to this summer’s big battle, an attempt to smash through the German lines at Ypres itself. So the fighting at Messines begins to wind down.
image source (Wikipedia)