Roy G Dieks vs Jan Timman
NED-ch Leeuwarden NED round 3 1975.04.09
Pirc Defense: Austrian Attack 0-1

Hans Ree vs Roy G Dieks
NED-ch Leeuwarden NED round 6 1975.04.12
King’s Indian Defense: Kazakh Variation 1-0

Alexander Beliavsky vs Roy G Dieks
Wch U20 prel-A Teesside round 3 1973.??.??
Sicilian Defense: Najdorf Variation 1-0