Jochem Boas was a son of Alexander Boas and Catharina Walvisch. From that marriage of his father, solemnized on 7 May 1873 in Amsterdam, Jochem had two brothers: Barend (who passed away in 1936 and who was married Klaartje Roet and Salomon , who was unmarried.
From the second marriage of his father Alexander Boas to Rachel Koen on 24 November 1886 in Amsterdam, Jochem had two more sisters: Roosje…