Censorship in wartime is nothing special. What happened with this postcard from the occupied Netherlands (31-05-1940) to Batavia, Dutch East Indies, is therefore not rare. The two-line red stamp “Gecensureerd” (censored) is very common.
Many Dutch (mainly) young men were in World War Two forced to work in Germany especially in the (war) industry. One of the worked for the pistols factory Mauser-Werken in Oberndorf (Neckar). The letter was sent by his father from Winsum (Gn.) 19.3.1945.