| Jul 13, 2025 | Kliewe | 0–1 | Kolthoff | Round 7: Kliewe, Hans-Juergen - Kolthoff, Siegmund | East Indian Defense | |
| Jul 12, 2025 | Kolthoff | 1–0 | Barten | Round 6: Kolthoff, Siegmund - Barten, Ralf | Slav Defense: Modern Line | |
| Jul 11, 2025 | Wagner | 0–1 | Kolthoff | Round 5: Wagner, Bernd - Kolthoff, Siegmund | London System | |
| Jul 10, 2025 | Kolthoff | 1–0 | Broeder | Round 4: Kolthoff, Siegmund - Broeder, Hans-Gert | Slav Defense: Quiet Variation, Schallopp Defense | |
| Jul 9, 2025 | Boettcher | ½–½ | Kolthoff | Round 3: Boettcher, Frank, Dr. - Kolthoff, Siegmund | English Opening: Symmetrical Variation, Anti-Benoni Variation, Spielmann Defense | |
| Jul 8, 2025 | Kolthoff | 0–1 | Cordes | Round 2: Kolthoff, Siegmund - Cordes, Lothar | English Opening: Symmetrical Variation, Full Symmetry Line | |
| Jul 7, 2025 | Gismann | 0–1 | Kolthoff | Round 1: Gismann, Juergen, Dr. - Kolthoff, Siegmund | Sicilian Defense: Staunton-Cochrane Variation | |
| Apr 4, 2025 | Pollmann | ½–½ | Kolthoff | Round 7: Pollmann, Sascha - Kolthoff, Siegmund | King's Indian Attack | |
| Apr 2, 2025 | Schneider-Zinner | 1–0 | Kolthoff | Round 5: Schneider-Zinner, Harald - Kolthoff, Siegmund | Nimzo-Larsen Attack: Classical Variation | |
| Apr 1, 2025 | Kolthoff | ½–½ | Belke | Round 4: Kolthoff, Siegmund - Belke, Frank, Dr. | London System | |
| Mar 31, 2025 | Kolthoff | 1–0 | Nikolov | Round 3: Kolthoff, Siegmund - Nikolov, Jordan | English Opening: King's English Variation, Kramnik-Shirov Counterattack | |
| Mar 29, 2025 | Kolthoff | 1–0 | Samisch | Round 1: Kolthoff, Siegmund - Samisch, Romuald | Queen's Gambit Declined: Janowski Variation | |
| Jul 7, 2024 | Kolthoff | 1–0 | Cordes | Round 7: Kolthoff, Siegmund - Cordes, Lothar | Catalan Opening | |
| Jul 6, 2024 | Renner | ½–½ | Kolthoff | Round 6: Renner, Bernd - Kolthoff, Siegmund | Sicilian Defense | |
| Jul 5, 2024 | Kolthoff | ½–½ | Poetke | Round 5: Kolthoff, Siegmund - Poetke, Dan-Peter | English Opening: Anglo-Grünfeld Defense | |
| Jul 3, 2024 | Kolthoff | 1–0 | Colin Costello | Round 3: Kolthoff, Siegmund - Colin Costello | Bogo-Indian Defense: Grünfeld Variation | |
| Jul 2, 2024 | Just | 0–1 | Kolthoff | Round 2: Just, Joachim - Kolthoff, Siegmund | English Opening: Symmetrical Variation, Three Knights Variation | |
| Jul 1, 2024 | Kolthoff | * | Waagener | Round 1: Kolthoff, Siegmund - Waagener, Ulrich | Zukertort Opening: Queen's Gambit Invitation | |
| Jul 1, 2024 | Kolthoff | 1–0 | Schwarz | Round 1: Kolthoff, Siegmund - Schwarz, Hans | Zukertort Opening: Queen's Gambit Invitation | |
| Jul 1, 2024 | Kahe | 1–0 | Kolthoff | Round 4: Kahe, Ralph - Kolthoff, Siegmund | Nimzo-Indian Defense: Classical Variation, Noa Variation | |
| Apr 8, 2024 | Cordts | ½–½ | Kolthoff | Round 3: Cordts, Ingo - Kolthoff, Siegmund | Catalan Opening: Closed | |
| Oct 28, 2023 | Lammers | 1–0 | Kolthoff | 26. Offene Internationale Bayerische Schachmeisterschaft Tegernsee | Slav Defense: Quiet Variation, Schallopp Defense | |
| Sep 11, 2023 | Richter | ½–½ | Kolthoff | 20. RLP-Senioren-Open | Semi-Slav Defense: Meran Variation, Wade Variation | |
| Sep 10, 2023 | Kolthoff | ½–½ | Wacker | 20. RLP-Senioren-Open | Caro-Kann Defense: Exchange Variation, Rubinstein Variation | |
| Sep 9, 2023 | Polster | ½–½ | Kolthoff | 20. RLP-Senioren-Open | Rapport-Jobava System | |
| Sep 8, 2023 | Kolthoff | 1–0 | Hesse | 20. RLP-Senioren-Open | Ruy Lopez: Closed, Flohr System | |
| Sep 7, 2023 | Schwickert | ½–½ | Kolthoff | 20. RLP-Senioren-Open | Zukertort Opening: Nimzo-Larsen Variation | |
| Sep 6, 2023 | Kolthoff | ½–½ | Wegemund | 20. RLP-Senioren-Open | Tarrasch Defense: Classical Variation, Advance Variation | |
| Sep 5, 2023 | Klein | 0–1 | Kolthoff | 20. RLP-Senioren-Open | Sicilian Defense: Kan Variation, Modern Variation | |
| Nov 12, 2022 | Kolthoff | * | Mazatis | 25th Open Bavarian Championship | ? | |
| Nov 11, 2022 | Degenhard | 1–0 | Kolthoff | 25th Open Bavarian Championship | ? | |
| Nov 10, 2022 | Kolthoff | ½–½ | Joel Paul Ganta | 25th Open Bavarian Championship | ? | |
| Nov 9, 2022 | Player | ½–½ | Kolthoff | 25th Open Bavarian Championship | Bishop's Opening: Berlin Defense | |
| Nov 8, 2022 | Kolthoff | 1–0 | Smits | 25th Open Bavarian Championship | ? | |
| Nov 7, 2022 | Boehmer | ½–½ | Kolthoff | 25th Open Bavarian Championship | ? | |
| Nov 6, 2022 | Kolthoff | ½–½ | Kannenberg | 25th Open Bavarian Championship | ? | |
| Jul 22, 2022 | Kolthoff | * | Gentemann | open | ? | |
| Jul 21, 2022 | Homberger | * | Kolthoff | open | ? | |
| Jul 19, 2022 | Gottmann | * | Kolthoff | open | ? | |
