| Mar 31, 2026 | Heermann | ½–½ | Wetterau | Runde 8: Heermann, Kai - Wetterau, Georg | Neo-Grünfeld Defense: Classical Variation, Original Defense | |
| Mar 29, 2026 | Heermann | 1–0 | Nattermueller | Runde 5: Heermann, Kai - Nattermueller, Matthias | Queen's Gambit Declined: Orthodox Defense, Rubinstein Attack | |
| Mar 27, 2026 | Fistoul | 1–0 | Heermann | Runde 9: Fistoul, Boris - Heermann, Kai | Mexican Defense | |
| Mar 27, 2026 | Grozea | ½–½ | Heermann | Runde 7: Grozea, Filip - Heermann, Kai | Caro-Kann Defense: Advance Variation, Botvinnik-Carls Defense | |
| Mar 27, 2026 | Heermann | 1–0 | Wolfer | Runde 6: Heermann, Kai - Wolfer, Noah | Queen's Pawn Game: Colle System | |
| Oct 24, 2025 | Westerhoff | 1–0 | Heermann | Stadtpokal Vechta 2025 | Queen's Indian Defense: Fianchetto Variation, Sämisch Variation | |
| Jul 28, 2024 | Heermann | * | Tonndorf | Round 6: Heermann, Kai - Tonndorf, Matthias | ? | |
| Jul 28, 2024 | Miowitz | ½–½ | Heermann | Round 7: Miowitz, Torsten - Heermann, Kai | Slav Defense: Schlechter Variation | |
| Jul 27, 2024 | Heermann | 0–1 | Okrajek | Round 5: Heermann, Kai - Okrajek, Alexander | King's Indian Defense: Normal Variation, King's Knight Variation | |
| Jul 27, 2024 | Reichelt | 0–1 | Heermann | Round 4: Reichelt, Ole - Heermann, Kai | Benoni Defense: Benoni Gambit Accepted | |
| Jul 26, 2024 | Heermann | ½–½ | de Vries | Round 3: Heermann, Kai - de Vries, Carsten | Catalan Opening: Open Defense | |
| Jul 26, 2024 | Solbu | 0–1 | Heermann | Round 2: Solbu, August - Heermann, Kai | Caro-Kann Defense: Exchange Variation, Rubinstein Variation | |
| Jul 25, 2024 | Heermann | ½–½ | Kutz | Round 1: Heermann, Kai - Kutz, Ida Klara | King's Indian Defense: Normal Variation, Standard Development | |
| Jun 9, 2024 | Heermann | 0–1 | Elsner | Round 4: Heermann, Kai - Elsner, Robert | Catalan Opening: Open Defense, Classical Line | |
| Jun 8, 2024 | Rennkamp | 1–0 | Heermann | Round 3: Rennkamp, Johannes - Heermann, Kai | Queen's Pawn Game: Zukertort Variation | |
| Jun 8, 2024 | Nordhorn | 0–1 | Heermann | Round 2: Nordhorn, Horst - Heermann, Kai | King's Indian Attack | |
| — | Heermann | ½–½ | Herter | Round 2: Heermann, Kai - Herter, Arne | Rapport-Jobava System | |
| — | Heermann | 0–1 | Muendoerfer | Round 4: Heermann, Kai - Muendoerfer, Sebastian | Queen's Indian Defense: Fianchetto Variation, Sämisch Variation | |
| — | Heermann | 1–0 | Dohmeyer | Round 7: Heermann, Kai - Dohmeyer, Joern | Dutch Defense: Hopton Attack | |
| — | Ohme | 0–1 | Heermann | Round 1: Ohme, Leon - Heermann, Kai | Rapport-Jobava System | |
| — | Stern | 0–1 | Heermann | Round 3: Stern, Philipp - Heermann, Kai | Caro-Kann Defense: Advance Variation, Botvinnik-Carls Defense | |
| — | Thomas | 1–0 | Heermann | Round 5: Thomas, Jeremy - Heermann, Kai | Caro-Kann Defense: Tartakower Variation | |
| — | Martin | 1–0 | Heermann | Round 6: Martin, Dennis - Heermann, Kai | Caro-Kann Defense: Advance Variation, Tal Variation | |
