Jacob Blanes was a son of David Blanes and Sophie Buitenkant. His father consecutively worked as a diamond worker, a depot manager, a supervisor of kashrut and an agent. The family lived in Paris, where Jacob was born. Upon returning to Amsterdam, the family lived at 51 Weesperstraat.
Jacob attended the Ets Haim institute of the Portuguese-Jewish community. He completed his training as a middle-gr…