Johnny van der Sluis was a son of Israël van der Sluis and Betje Cohen. He was born on 4 August 1924 in the Molenaerstraat 30a in Haarlem. With his parents, he moved from Haarlem to Korte Mare 23 in Leiden in the later years of then 1930-s.
From data of the Jewish Lyceum Den Haag, it appears that Johnny attended the 4th class of the HBS department there in the scholastic year 1941/1942 and that he…