Kammala jumla mai zuwa: Daga ƙarshen 1930s zuwa farkon 1940s, Stoffels na ɗaya daga cikin manyan 'yan wasan chess mata a Belgium. Ta lashe gasar zakarun mata ta Belgian sau biyar: a 1938, 1939, 1940, 1942 da 1944. Ta halarci sau da yawa a gasar cin kofin kulob din Antwerp "De Zilveren toren" tare da kulob din chess na Antwerp "Het schaakbord" daga 1929 zuwa 1934. A shekara ta 1939, Stoffels ya shiga cikin
Gasar Cin Kofin Duniya ta Mata ta 1939 a Buenos Aires, inda ta gama a matsayi na 16.