Dutch Chess composer, a lawyer, and a diplomat. International Judge for Chess Compositions (1951).
One of the founders of FIDE at Paris 1924 and first FIDE President (1924-49). FIDE Honorary President of FIDE (1949-59). He was also president of the Dutch chess federation 1923-28. A chess bibliophile, he bequeathed his collection of chess books to the University of Amsterdam. Author ofBronnen van Schaakstudie, consisting of five volumes.