| Game |
| Result | Moves |
Year | Event/Locale | Opening |
| 1. T Baumstark vs O Koeller |
| ½-½ | 32 | 1993 | Kassel op | B06 Robatsch |
| 2. M Schoeneich vs O Koeller |
| 1-0 | 26 | 1994 | Berliner Sommer | B07 Pirc |
| 3. T Oparaugo vs O Koeller |
| 1-0 | 46 | 1994 | Berliner Sommer | B07 Pirc |
| 4. M Miersch vs O Koeller |
| ½-½ | 11 | 1994 | Berliner Sommer | B07 Pirc |
| 5. O Koeller vs U Parske |
| ½-½ | 11 | 1994 | Berliner Sommer | C07 French, Tarrasch |
| 6. A Korotylev vs O Koeller |
| 1-0 | 32 | 1995 | Passau op 3rd | E70 King's Indian |
| 7. O Koeller vs S Reschke |
| 1-0 | 24 | 1997 | Biel MTO op | B76 Sicilian, Dragon, Yugoslav Attack |
| 8. Adianto vs O Koeller |
| 1-0 | 40 | 1997 | Biel | D70 Neo-Grunfeld Defense |
| 9. O Koeller vs F Doettling |
| ½-½ | 33 | 1997 | Vierlaenderkampf | B18 Caro-Kann, Classical |
| 10. H Teske vs O Koeller |
| ½-½ | 26 | 1998 | Danube Open | A35 English, Symmetrical |
| 11. O Koeller vs H Park |
| 1-0 | 22 | 1999 | Bad Zwesten Open | B01 Scandinavian |
| 12. O Koeller vs W Zoch |
| 1-0 | 27 | 1999 | Bad Zwesten Open | B93 Sicilian, Najdorf, 6.f4 |
| 13. R Wahrenberg vs O Koeller |
| 0-1 | 46 | 1999 | Bad Zwesten Open | A40 Queen's Pawn Game |
| 14. A Shchekachev vs O Koeller |
| 1-0 | 38 | 1999 | Bad Zwesten Open | B01 Scandinavian |
| 15. O Koeller vs G Richter |
| 1-0 | 52 | 1999 | Bad Zwesten Open | B89 Sicilian |
| 16. L Gutman vs O Koeller |
| 1-0 | 63 | 1999 | Bad Zwesten Open | E61 King's Indian |
| 17. O Koeller vs R Gruettner |
| 1-0 | 35 | 1999 | Bad Zwesten Open | B77 Sicilian, Dragon, Yugoslav Attack |
| 18. O Koeller vs G Goessling |
| ½-½ | 38 | 1999 | Bad Zwesten Open | C45 Scotch Game |
| 19. M Kiese vs O Koeller |
| ½-½ | 37 | 1999 | Bad Zwesten Open | E70 King's Indian |
| 20. O Koeller vs D Tyomkin |
| 0-1 | 47 | 1999 | Biel MTO op | B57 Sicilian |
| 21. O Koeller vs G Aschauer |
| 1-0 | 56 | 1999 | Danube Open | B87 Sicilian, Fischer-Sozin with ...a6 and ...b5 |
| 22. F Brandstaetter vs O Koeller |
| ½-½ | 57 | 1999 | Danube Open | B78 Sicilian, Dragon, Yugoslav Attack, 10.castle long |
| 23. O Koeller vs H Genser |
| ½-½ | 12 | 1999 | Danube Open | A13 English |
| 24. K Hansen vs O Koeller |
| ½-½ | 13 | 1999 | Danube Open | A45 Queen's Pawn Game |
| 25. O Koeller vs W Kugelmann |
| 0-1 | 17 | 1999 | Danube Open | B33 Sicilian |
Kibitzing
