1./JG 20 was established primarily from elements of JG 2 in Döberitz on 15 July 1939. The unit was subsequently re-designated 7./JG 51 in mid-1940. Oblt. Walter Oesau was the first Staffelkapitän. The Staffel 'Pfeil und Bogen' emblem can be seen on the cowl of the Emil in the image above.. which may or may not be Oesau's 'white 1'...or 'white 13'.
Below; tail of Oesau's WNr. 1432 'white 1' with 10 Abschuss markings dating this image to mid-July 1940 - each kill is dated and the aircraft type noted. The 'kill' marking closest to the rudder hinge line is marked 'Defiant' - Oesau claimed a 141 Sqd Defiant shot down on 19 July 1940. Oesau was awarded the Ritterkreuz during August 1940, the fifth Jagdwaffe pilot to achieve the award..the second image shows the tail of his 'white 13' much later in the Battle of Britain..
here
Messerschmitt Bf 109 E4 7./JG 51 'White 13' Walter Oesau WNr 1432 during late August-September 1940
Also on this blog
Walter Oesau and JG 20 in the French campaign
Kommodore Oesau's last sortie May 1944 JG 1 Bf 109 G-6/AS
the aces of JG 2 victory claims and credits during 1941
Maj. Walter Oesau JG 2 100th Luftsieg October 1941 Channel Front Aces