EU-ch U20 clock sim2
Groningen 1966
| Date | Players | Type | Elo Average | Games | Rounds |
| Dec, 1966 | 11 | Simul | 10 | 1 |
| Name | ELO | Points | ||
| Donner, Jan Hein | 6.0 | |||
| Vadasz, Laszlo | 1.0 | |||
| Feenstra, JA. | 0.5 | |||
|
Kiers, Conrad | 0.5 | ||
 |
Pedersen, Svend | 0.5 | ||
| Seslija, Dragan | 0.5 | |||
 |
FM Westermeier, Arnulf | 0.5 | ||
 |
IM Whiteley, Andrew J | 0.5 | ||
|
Algera, Simon | 0.0 | ||
 |
FM Gralka, Julian | 0.0 | ||
| Zara, Dan | 0.0 | |||
EU-ch U20 clock sim2 Games
| White | Black | Result | Round | Date | Opening | View |
| Donner, J | Algera, S | 1-0  |
? | 1966 | A99 Dutch, Ilyin-Genevsky variation with b3 |   |
| Donner, J | Feenstra, J | ½-½ |
? | 1966 | A52 Budapest defence |   |
| Donner, J | Gralka, J | 1-0 |
? | 1966 | A56 Benoni defence | |
| Donner, J | Kiers, C | ½-½ |
? | 1966 | E52 Nimzo-Indian, 4.e3, main line with ...b6 | |
| Donner, J | Pedersen, S | ½-½ |
? | 1966 | B09 Pirc, Austrian attack | |
| Donner, J | Seslija, D | ½-½ |
? | 1966 | D36 Queen's Gambit Declined, exchange, positional line, 6.Qc2 | |
| Donner, J | Vadasz, L | 0-1 |
? | 1966 | A55 Old Indian, main line | |
| Donner, J | Westermeier, A | ½-½ |
? | 1966 | D36 Queen's Gambit Declined, exchange, positional line, 6.Qc2 | |
| Donner, J | Whiteley, A | ½-½ |
? | 1966 | D44 Queen's Gambit Declined semi-Slav, 5.Bg5 dc | |
| Donner, J | Zara, D | 1-0 |
? | 1966 | D37 Queen's Gambit Declined, 4.Nf3 | |