Heroes memorial day (Heldengedenktag) stamps from 1942. Designed by Richard Klein.
 
They come as a strip of 5 stamps.
 
Heldengedenktag was established and celebrated as national holiday in the Third Reich from 1934 till the end of the war in 1945.  It's been replaced since 1952 by a rescheduled holiday Volkstrauertag (people's day of mourning) devoted not to soldiers only, but also people killed by evil regimes.