Hartog Jas was a son of Isaac Jas and Grietje Hakker. He married Klara van der Sluis in Amsterdam op 12 June 1907, a daughter of Joseph van der Sluis and Esther Spaanbroek.
The couple had sixteen children together, of whom Marianna passed, only 12 days old. Probably a daughter Margaretha has died in childhood too. Their sons Joseph, Frederik, Isaac and Gerrit and a daughter Vrouwtje have survived…