46 games in the PremovedPrep archive. Games as White.
| White | Black | Result | ECO | Event | Date |
|---|---|---|---|---|---|
| Koster, Chiel | Wang, Jake | 1-0 | B42 | Round 4: Koster, Chiel - Wang, Jake | 2025-09-13 |
| Koster, Chiel | Jordan, Felix | 1-0 | D77 | Round 2: Koster, Chiel - Jordan, Felix | 2025-09-12 |
| Koster, Chiel | Kurt, Sascha | 1/2-1/2 | A27 | Round 5: Koster, Chiel - Kurt, Sascha | 2025-06-08 |
| Koster, Chiel | Kazarjan, Gachatur | 1/2-1/2 | D34 | Round 5: Koster, Chiel - Kazarjan, Gachatur | 2025-05-18 |
| Koster, Chiel | De Vries, Emma | 1-0 | D79 | Round 2: Koster, Chiel - De Vries, Emma | 2025-05-17 |
| Koster, Chiel | Grooten, Tommy | 1/2-1/2 | B90 | Round 9: Koster, Chiel - Grooten, Tommy | 2024-08-01 |
| Koster, Chiel | Buckels, Valentin | 0-1 | B10 | Round 7: Koster, Chiel - Buckels, Valentin | 2024-07-30 |
| Koster, Chiel | Smit, Manuel | 1-0 | A15 | Round 5: Koster, Chiel - Smit, Manuel | 2024-07-27 |
| Koster, Chiel | Shakhverdian, William | 0-1 | E66 | Round 3: Koster, Chiel - Shakhverdian, William | 2024-07-25 |
| Koster, Chiel | Grooten, Herman | 1/2-1/2 | B10 | Round 1: Koster, Chiel - Grooten, Herman | 2024-07-23 |
| Koster, Chiel | Baselmans, Sam | 0-1 | C55 | WLC Tournament 2024 A | 2024-06-02 |
| Koster, Chiel | Beerdsen, Thomas | 0-1 | B10 | WLC Tournament 2024 A | 2024-06-01 |
| Koster, Chiel | Kools, Thomas | 1/2-1/2 | A25 | WLC Tournament 2024 A | 2024-06-01 |
| Chiel Koster | Tjark Vos | 0-1 | C24 | Round 7: Chiel Koster - Tjark Vos | 2023-08-01 |
| Chiel Koster | Jakob Weidemann | 1-0 | B33 | Round 5: Chiel Koster - Jakob Weidemann | 2023-07-29 |
| Chiel Koster | Eelke De Boer | 0-1 | A00 | Round 3: Chiel Koster - Eelke De Boer | 2023-07-27 |
| Chiel Koster | Nick Maatman | 0-1 | C01 | Round 1: Chiel Koster - Nick Maatman | 2023-07-25 |
| Koster, Chiel | Sprangers, Remco | 1-0 | B90 | WLC Toernooi 2023 A | 2023-05-07 |
| Koster, Chiel | Baselmans, Luuk | 1-0 | C00 | WLC Toernooi 2023 A | 2023-05-06 |
| Koster, Chiel | Kools, Jasper | 1/2-1/2 | B42 | WLC 2022 A | |
| Koster, Chiel | Van Helvoort, Rob | 1-0 | B06 | WLC 2022 A | |
| Koster, Chiel | Van Roon, Sjoerd | 1/2-1/2 | B90 | WLC 2022 A |