第三次ハリコフ攻防戦
Barkmann joined the Nazi Party on 1 September 1938 and served in the Reich Labour Service from November 1938 to March 1939. After this he joined the SS on 1 April 1939, and served during the occupation of Poland. He was posted for a time as an instructor of SS volunteers in the Netherlands. In winter 1942/43 he was posted to the SS Division Das Reich on the Eastern Front, with which he took part in the Third Battle of Kharkov.