In 1937, Heinz Erwin van Mindeno became a junior member of the Vereenigd Amsterdamsch Schaak Genootschap (the Amsterdam chess association) and managed to attain the title of 'first-class' player (the national level just below that of master).
Partij verloren Gedenkboek ter herinnering aan de schakers die in Nederland tijdens de bezetting heengingen. Eggink en Schelfhout, Amsterdam, 1947, p. 204