J. Koolhoven
Last tournaments played
| Tournament | Date | Elo Avg. | Country |
| Vlissingen op | 07/??/1996 | 668 | Netherlands |
| Vlissingen op | ??/??/1995 | 649 | Netherlands |
Most Played Openings as White
| ECO | Opening | Games |
| B33 | Sicilian defence | 1 games |
| C47 | Four knights, Scotch variation | 1 games |
| C01 | French, exchange variation | 1 games |
| B01 | Scandinavian (centre counter) defence | 1 games |
Most Played Openings as Black
| ECO | Opening | Games |
| A40 | Queen's pawn | 1 games |
| E73 | King's Indian, 5.Be2 | 1 games |
| B50 | Sicilian | 1 games |
| B95 | Sicilian, Najdorf, 6...e6 | 1 games |


Netherlands