| May 30, 2026 | Heidemann | 1–0 | Othman | DEM U18w 2026 | Sicilian Defense: Alapin Variation, Smith-Morra Declined | |
| May 29, 2026 | Lorenz | 1–0 | Heidemann | DEM U18w 2026 | Sicilian Defense: Hyperaccelerated Dragon | |
| May 28, 2026 | Heidemann | 1–0 | Neumann | DEM U18w 2026 | Zukertort Opening | |
| May 27, 2026 | Heidemann | 1–0 | Bursan | DEM U18w 2026 | Sicilian Defense: Staunton-Cochrane Variation | |
| May 26, 2026 | Fock | 0–1 | Heidemann | DEM U18w 2026 | Scandinavian Defense: Valencian Variation, Main Line | |
| May 25, 2026 | Loos | 0–1 | Heidemann | DEM U18w 2026 | Sicilian Defense: Hyperaccelerated Dragon | |
| May 24, 2026 | Heidemann | 1–0 | Reich | DEM U18w 2026 | Sicilian Defense: Staunton-Cochrane Variation | |
| May 24, 2026 | Heidemann | 0–1 | Junge | DEM U18w 2026 | Caro-Kann Defense: Two Knights Attack, Mindeno Variation, Retreat Line | |
| May 15, 2026 | Wilmink | 1–0 | Heidemann | DEM U18w 2026 | Sicilian Defense: Hyperaccelerated Dragon | |
| Oct 29, 2025 | Heidemann | 0–1 | Mickunaite | Round 1: Heidemann, Nora - Mickunaite, Agne | Sicilian Defense: Staunton-Cochrane Variation | |
| Oct 16, 2025 | Heidemann | 0–1 | Aryan Goyal | Runde 7: Heidemann, Nora - Aryan Goyal | Catalan Opening: Open Defense, Classical Line | |
| Oct 14, 2025 | Heidemann | 0–1 | Razawi | Runde 5: Heidemann, Nora - Razawi, S.Ahmad Fahim | Sicilian Defense: Staunton-Cochrane Variation | |
| Oct 12, 2025 | Heidemann | 0–1 | Korschunow | Runde 3: Heidemann, Nora - Korschunow, Dennis | Caro-Kann Defense: Two Knights Attack | |
| Oct 12, 2025 | Alugili | 0–1 | Heidemann | Runde 2: Alugili, Yosef - Heidemann, Nora | Scandinavian Defense: Valencian Variation, Main Line | |
| Oct 11, 2025 | Heidemann | 0–1 | Lymar | Runde 1: Heidemann, Nora - Lymar, Vladislav | Scandinavian Defense: Mieses-Kotroc Variation | |
| Jun 11, 2025 | Sereda | 0–1 | Heidemann | DEM U18w 2025 | Sicilian Defense: Accelerated Dragon, Maróczy Bind, Gurgenidze Variation | |
| Jun 9, 2025 | Heidemann | 1–0 | Voigt | DEM U18w 2025 | Caro-Kann Defense: Two Knights Attack | |
| Jun 8, 2025 | Heidemann | 1–0 | Gyacsok | DEM U18w 2025 | Four Knights Game: Scotch Variation Accepted | |
| Jun 6, 2025 | Heidemann | ½–½ | Fischer | DEM U18w 2025 | English Opening: King's English Variation, Four Knights Variation, Fianchetto Line, with Nb6 | |
| Jun 6, 2025 | Jacobasch | 0–1 | Heidemann | DEM U18w 2025 | Rapport-Jobava System | |
| Jun 6, 2025 | Heidemann | ½–½ | Trunz | DEM U18w 2025 | English Opening: King's English Variation, Four Knights Variation, Fianchetto Line, with Nb6 | |
| Jun 6, 2025 | Fock | 0–1 | Heidemann | DEM U18w 2025 | Sicilian Defense: Accelerated Dragon, Modern Bc4 Variation | |
| Jun 6, 2025 | Heidemann | ½–½ | Neumann | DEM U18w 2025 | Sicilian Defense: Staunton-Cochrane Variation | |
| Jun 6, 2025 | Braeutigam | 0–1 | Heidemann | DEM U18w 2025 | Indian Defense | |
| Oct 18, 2024 | Heidemann | 0–1 | Darshan G | Round 8: Heidemann, Kristjan - Darshan G | Scotch Game: Malaniuk Variation | |
| Oct 17, 2024 | Boesel | 1–0 | Heidemann | Round 7: Boesel, Alexander - Heidemann, Kristjan | Sicilian Defense: Hyperaccelerated Dragon | |
| Oct 16, 2024 | Rott | 0–1 | Heidemann | Round 6: Rott, Georg - Heidemann, Kristjan | Sicilian Defense: Hyperaccelerated Fianchetto | |
| Oct 15, 2024 | Heidemann | ½–½ | Scholz | Round 5: Heidemann, Kristjan - Scholz, Benedict | Sicilian Defense: Staunton-Cochrane Variation | |
| Oct 14, 2024 | Schmitzer | 1–0 | Heidemann | Round 4: Schmitzer, Klaus - Heidemann, Kristjan | Trompowsky Attack | |
| Oct 13, 2024 | Heidemann | 1–0 | Jungbluth | Round 3: Heidemann, Kristjan - Jungbluth, Michael | French Defense: Tarrasch Variation, Guimard Defense, Main Line | |
| Aug 19, 2024 | Heidemann | 0–1 | Vagman | EYCC 2024 Blitz O16 | Barnes Opening | |
| Aug 19, 2024 | Vagman | 1–0 | Heidemann | EYCC 2024 Blitz O16 | English Opening | |
| Aug 18, 2024 | Heidemann | 0–1 | Szakmary | EYCC 2024 Rapid O16 | Barnes Opening | |
| Aug 18, 2024 | Zieba | 1–0 | Heidemann | EYCC 2024 Rapid O16 | Neo-Grünfeld Defense: Delayed Exchange Variation | |
| Aug 17, 2024 | Heidemann | 0–1 | Podolskyi | EYCC 2024 Rapid O16 | Sicilian Defense: Staunton-Cochrane Variation | |
| Aug 17, 2024 | Heidemann | 0–1 | Nesterenko | EYCC 2024 Rapid O16 | Scandinavian Defense: Modern Variation | |
| Jun 7, 2024 | Heidemann | 0–1 | Neumann | Round 11: Heidemann, Kristjan - Neumann, Helena | Neo-Grünfeld Defense: Classical Variation, Modern Defense | |
| Jun 7, 2024 | Heidemann | 1–0 | Hagenhoff | Round 9: Heidemann, Kristjan - Hagenhoff, Georg | French Defense: Tarrasch Variation, Pawn Center Variation | |
| Jun 7, 2024 | Heidemann | 1–0 | Heuermann | Round 7: Heidemann, Kristjan - Heuermann, Heinz-Burkhard | Sicilian Defense: Staunton-Cochrane Variation | |
| Jun 7, 2024 | Gerov | 0–1 | Heidemann | Round 5: Gerov, Emil - Heidemann, Kristjan | Sicilian Defense: Accelerated Dragon | |
| Jun 7, 2024 | Hofmann | 1–0 | Heidemann | Round 3: Hofmann, Martin - Heidemann, Kristjan | Grünfeld Defense: Exchange Variation, Modern Exchange Variation | |
| Jun 7, 2024 | Miller | 0–1 | Heidemann | Round 1: Miller, Hans-Werner - Heidemann, Kristjan | English Opening: Symmetrical Variation | |
