1940 Nay is conscripted into military service. He is sent as infantryman first to southern France, then to Brittany. Stationed in Auray, in his spare time he works on small watercolours and drawings. During a holiday leave at home in Berlin, Nay sends most of his paintings to an uncle in Muskau an der Lausitz to protect them from the effects of the war.
1942 Through mediation by Hans Lühdorf, who is on duty as interpreter in Le Mans, Nay becomes a cartographer in Le Mans. There he meets, among others, the amateur sculptor Pierre de Térouanne, who makes available to him his studio and even provides painting materials. Now gouaches emerge for the first time, along with watercolours and drawings, and some smaller oil paintings.
1943 On an official journey to Paris Nay visits Wassily Kandinsky. Ernst Jünger visits him in Le Mans. An air raid destroys Nay’s studio in Berlin.
1944 Nay’s unit retreats from Amiens to the Eifel. Lühdorf writes a diary-like account of Nay’s artistic work in Le Mans.
1945 As early as May the Americans dismiss Nay from the German army. Since his studio in Berlin is destroyed, he moves to Hofheim am Taunus into a small studio house, provided by Hanna Bekker vom Rath. Productive contacts occur with, for instance, Ernst Holzinger, director of the Städelsche Kunstinstitut, and the writer Fritz Usinger. Nay begins his work period of the “Hekate-Bilder” (1945–1948).