ZG 1 in heavy fighter operations. The unit fought in the Battle of the Netherlands. ZG 1 was engaged in the Offensive counter air operations against the Royal Dutch Air Force on 10 May. 4. Staffel is known to have fought in combat with the Dutch 5e JaVA (5th Fighter Unit) which cost it one aircraft. One flight of ZG 1 Bf 110s shot down five from six Bristol Blenheims from No. 600 Squadron RAF, which had taken off from RAF Manston to bomb Waalhaven. On 11 May RAF Bomber Command sent No. 18 and No. 53 to bomb the Albert Canal near Maastricht. Four Bristol Blenheims failed to return; one was a victim of JG 1, two to ground-fire, but the other fell to Bf 110s from II./ZG 1. ZG 1 continued counter-air operations by strafing airfields. I. and II. Gruppe attacked Haamstede, Flushing, and Oostvoorne. I./ZG 1 claimed 26 Dutch aircraft on the ground. True Dutch losses are unstated. The command flight of II./ZG 1 encountered No. 615 Squadron RAF and the British unit lost one pilot killed near Courrière. ZG 1 conducted patrols during the Battle of Gembloux, a major engagement in the Battle of Belgium, and accounted for a No. 87 Squadron RAF pilot killed near the town on 14 May. No. 87 and ZG 1 clashed again later in the day. Along with No. 79 Squadron RAF, they attempted to attack He 111s from II./LG 1 near Brussels. Three German bombers were shot down but it cost No. 79 Squadron one pilot killed. No. 87 Squadron lost one Hawker Hurricane and it spilot wounded in action with 1./ZG 1. The air battles were costly; over the 10 to 13 May, ZG 1 and ZG 26 lost five Bf 110s between them [breakdown unknown]. On 14 May 5./ZG 1 lost its Staffelkapitän Hauptmann Kiippers during a full-scale strafing of Vlissingen airfield. On 16 May, over Brussels, five 1./ZG 1 Bf 110s fought No. 85 and No. 87 Squadrons; the British claimed three though no losses were sustained; one German pilot was wounded. The German unit claimed one, though any RAF casualties in the dogfight are unstated. Later in the day, No. 3 Squadron RAF fighters killed one of ZG 1's crews in combat. In return, Squadron Leader P Gifford DFC was killed in action with 1./ZG 1. ZG 1 are known to have fought in the