| Game |
| Result | Moves |
Year | Event/Locale | Opening |
| 1. G Oskam vs J H Goud |
| 1-0 | 26 | 1899 | corr | C80 Ruy Lopez, Open |
| 2. G Oskam vs A Coenen |
 | 1-0 | 33 | 1900 | The Hague | A07 King's Indian Attack |
| 3. G Oskam vs R Loman |
| 0-1 | 30 | 1902 | Discendo Discimus Jubilee | C29 Vienna Gambit |
| 4. Pillsbury vs G Oskam |
| 0-1 | 30 | 1902 | Pillsbury Simul 47b, Den Haag | C31 King's Gambit Declined, Falkbeer Counter Gambit |
| 5. G Oskam vs Wursche |
| 0-1 | 29 | 1903 | Correspondence t | C55 Two Knights Defense |
| 6. Creyghton vs G Oskam |
| 1-0 | 42 | 1903 | Hilversum | B32 Sicilian |
| 7. R Loman vs G Oskam |
| ½-½ | 29 | 1903 | Blindfold simul, 8b | C42 Petrov Defense |
| 8. J Speet vs G Oskam |
| ½-½ | 37 | 1904 | Amsterdam | D32 Queen's Gambit Declined, Tarrasch |
| 9. G Oskam vs G Bollebakker |
| ½-½ | 24 | 1904 | Amsterdam | A84 Dutch |
| 10. G Oskam vs H Meijer |
| ½-½ | 65 | 1904 | Amsterdam | A36 English |
| 11. G Oskam vs H J den Hertog |
| 0-1 | 19 | 1904 | Leeuwarden | C29 Vienna Gambit |
| 12. K Geus vs G Oskam |
 | 1-0 | 32 | 1905 | Easter Tournament | D32 Queen's Gambit Declined, Tarrasch |
| 13. G Oskam vs R Loman |
| 0-1 | 28 | 1905 | Scheveningen | C44 King's Pawn Game |
| 14. G Oskam vs D Bleijkmans |
| 0-1 | 43 | 1905 | Scheveningen | C30 King's Gambit Declined |
| 15. Marshall vs G Oskam |
| 1-0 | 26 | 1905 | Scheveningen | D32 Queen's Gambit Declined, Tarrasch |
| 16. G Oskam vs A Reggio |
| ½-½ | 64 | 1905 | Scheveningen | C29 Vienna Gambit |
| 17. G Schories vs G Oskam |
| 1-0 | 31 | 1905 | Scheveningen | B25 Sicilian, Closed |
| 18. Swiderski vs G Oskam |
| 1-0 | 27 | 1905 | Scheveningen | D11 Queen's Gambit Declined Slav |
| 19. G Oskam vs Spielmann |
| 1-0 | 41 | 1905 | Scheveningen | C44 King's Pawn Game |
| 20. G Oskam vs C Trimborn |
| 0-1 | 48 | 1905 | Scheveningen | D51 Queen's Gambit Declined |
| 21. Duras vs G Oskam |
| 1-0 | 26 | 1905 | Scheveningen | C65 Ruy Lopez, Berlin Defense |
| 22. G Oskam vs J Esser |
| 0-1 | 18 | 1905 | Scheveningen | C54 Giuoco Piano |
| 23. J W te Kolste vs G Oskam |
| 0-1 | 68 | 1905 | Scheveningen | C82 Ruy Lopez, Open |
| 24. G Oskam vs P Leonhardt |
| ½-½ | 32 | 1905 | Scheveningen | C67 Ruy Lopez |
| 25. B Leussen vs G Oskam |
| ½-½ | 33 | 1905 | Scheveningen | D32 Queen's Gambit Declined, Tarrasch |
Kibitzing
