M. Jonkman
Last tournaments played
| Tournament | Date | Elo Avg. | Country |
| NED-ch20 | ??/??/1961 | 0 |  Netherlands |
| NED-ch | ??/??/1958 | 0 | Netherlands |
Most Played Openings as White
| ECO | Opening | Games |
| E94 | King's Indian, orthodox variation | 1 games |
| E67 | King's Indian, fianchetto with ...Nd7 | 1 games |
| E63 | King's Indian, fianchetto, Panno variation | 1 games |
| D20 | Queen's gambit accepted | 1 games |
Most Played Openings as Black
| ECO | Opening | Games |
| A07 | Reti, King's Indian attack (Barcza system) | 1 games |
| C62 | Ruy Lopez, old Steinitz defence | 1 games |
| C18 | French, Winawer, advance variation | 1 games |
| A54 | Old Indian, Ukrainian variation | 1 games |
