Dutch Grandmaster (2002). Dutch U16 Champion in 1991.
Best results: Sonnevanck B 1995, 2nd; Leeuwarden and Den Hague 1998, 2nd; Den Haag 1999 and 2000, 1st; Bussum 2000, 1st; German U20 Championship 2004, 2nd and Banyoles Open and Harlem BDO 2005, 1st, Cusco 2006 (PER), 1st.
Harmen is retired from international chess since the end of 2008, he is just playing few league games per year.
