II.Gruppe Jagdgeschwader 1 "Oesau" (II./JG 1) was created on 15 January 1942 in Katwijk, Netherlands. Formed from I./JG 3, its first Gruppekommandeur was Hauptman Hans von Hahn, the previous commanding officer of I./JG 3.

Originally consisting of one GruppenStab (Stab II./JG 1) and three Staffeln (4./JG 1, 5./JG 1 and 6./JG 1), the Gruppe’s unit emblem was the Tatzelwurm, a mythical Norse serpent which had been adopted from I./JG 3 during its re-organization.

As a mid-to-late war daylight fighter unit, II./JG 1 was primarily concerned with the defense of “Gröss Deutschland”, which comprised all of Germany and the annexed territories of Austria and Western Czechoslovakia. In this role, the unit served almost exclusively in the Netherlands until 13 July 1943, where it was then transferred to Central and Western Germany.

In September of 1943, Geschwaderkommadore Obstlt. Walter Oesau introduced a new emblem that was to be used by all JG 1 Gruppen - a red winged ‘1’ in a white diamond, which was enclosed in a black circle. II./JG 1, like I./JG 1, quickly adopted this symbol in place of their traditional markings.

In June of 1944, II./JG 1 would serve in France, helping to defend the skies over the beaches of Normandy. On 15 August 1944, II./JG 1 was increased to four staffeln- 4./JG 1 was converted into 7./JG1 and 8./JG1 was formed from 7./JG 51. From this point until 1945, II./JG 1 would consist of it's GruppenStab, Stab II./JG 1, as well as 5., 6., 7. and 8./JG 1

With the Allied breakthrough at the Normandy beachhead, II./JG 1 was then assigned to help support preparations for the Ardennes counter-offensive, which would culminate in Operation Bodenplatte and the Battle of the Bulge in December 1944 and January 1945.

Failing to maintain air superiority over the Ardennes, II./JG 1 was then transferred from Western Germany to Insterburg within East Prussia. Here, they were briefly assigned to Luftflotte Reich (the Air Fleet assign to defend what was left of Germany from the final Allied offensives).

It was during this time that the Gruppe began converting to the He 162A Salamander, the focal point of the German “Volksjager” program. By March of 1945, II./JG 1 had transferred to Warnemünde for training in these new lightweight jet propelled fighters, and by April, the unit’s battle tested Fw 190A’s had been left at Garz /Usedom, Germany.

These new jet aircraft would never see wide-spread combat with II./JG 1, however. Allied Air Superiority had long ago become Air Supremacy, and with a shortage of both pilots, aircraft and petrol, the four Staffeln of II./JG 1 could no longer field their full complement or effectively perform their duties. As a result, on 8 April 1945, 8./JG 1 was disbanded. Then, on the 30 April 1945, II./JG 1 was combined with I./JG 1 at Leck in order to form two new Gruppen: I. (Einsatz)/JG 1 and II. (Sammel)/JG 1. Together, they shared a combined total of about 50 pilots and aircraft.

With this last desperate re-organization, the original II./JG 1 ceased to exist, and within seven days, the European Theatre of World War Two would come to an end.