| Game |
| Result | Moves |
Year | Event/Locale | Opening |
| 1. J L Marckens vs S Duran Vega |
| 1-0 | 44 | 2014 | Tromso Olympiad | B90 Sicilian, Najdorf |
| 2. Andrew Hale vs J L Marckens |
| 1-0 | 49 | 2014 | Tromso Olympiad | B13 Caro-Kann, Exchange |
| 3. J L Marckens vs A Santos Flores |
| 0-1 | 62 | 2014 | Tromso Olympiad | C01 French, Exchange |
| 4. Yu Tien Poon vs J L Marckens |
| 1-0 | 44 | 2014 | Tromso Olympiad | D76 Neo-Grunfeld, 6.cd Nxd5, 7.O-O Nb6 |
| 5. J C Hernandez vs J L Marckens |
| 1-0 | 85 | 2014 | Tromso Olympiad | D94 Grunfeld |
| 6. B Garcia vs J L Marckens |
| 0-1 | 57 | 2014 | Tromso Olympiad | A15 English |
| 7. M M Leye vs J L Marckens |
| ½-½ | 43 | 2014 | Tromso Olympiad | D94 Grunfeld |
| 8. J L Marckens vs O Amba |
| 0-1 | 46 | 2014 | Tromso Olympiad | B54 Sicilian |
| 9. J L Marckens vs J Jallow |
| 1-0 | 56 | 2014 | Tromso Olympiad | C60 Ruy Lopez |
| 10. J L Marckens vs W Kobese |
| 0-1 | 51 | 2018 | Batumi Olympiad | C78 Ruy Lopez |
| 11. A Bai vs J L Marckens |
| 1-0 | 55 | 2018 | Batumi Olympiad | D70 Neo-Grunfeld Defense |
| 12. Adama Mawulikplimi Ephoevi-Ga vs J L Marckens |
 | 0-1 | 68 | 2018 | Batumi Olympiad | A22 English |
| 13. J L Marckens vs M Alharari |
| 1-0 | 49 | 2018 | Batumi Olympiad | B01 Scandinavian |
| 14. J L Marckens vs Wazwaz Amjad |
| 1-0 | 28 | 2018 | Batumi Olympiad | C45 Scotch Game |
| 15. A H Abdulgalil Saleh vs J L Marckens |
| 0-1 | 24 | 2018 | Batumi Olympiad | B13 Caro-Kann, Exchange |
| 16. J L Marckens vs M H Ralison |
| 0-1 | 34 | 2018 | Batumi Olympiad | B87 Sicilian, Fischer-Sozin with ...a6 and ...b5 |
| 17. S Fancy vs J L Marckens |
| 0-1 | 36 | 2018 | Batumi Olympiad | B10 Caro-Kann |
| 18. J L Marckens vs Mohd Omar Ak Hira Pg |
| 1-0 | 85 | 2018 | Batumi Olympiad | B30 Sicilian |
| 19. J L Marckens vs I Efimov |
| 0-1 | 58 | 2018 | Batumi Olympiad | B43 Sicilian, Kan, 5.Nc3 |
| 20. Luis Miguel Aguilar vs J L Marckens |
| 0-1 | 46 | 2018 | Batumi Olympiad | A00 Uncommon Opening |
| 21. M Bailey vs J L Marckens |
| 0-1 | 48 | 2020 | FIDE Online Olympiad | E38 Nimzo-Indian, Classical, 4...c5 |
| 22. M Ortega Amarelle vs J L Marckens |
| 1-0 | 34 | 2020 | FIDE Online Olympiad | A28 English |
| 23. S M Tracey vs J L Marckens |
| 1-0 | 28 | 2020 | FIDE Online Olympiad | B13 Caro-Kann, Exchange |
| 24. J L Marckens vs S Boidiya |
| 1-0 | 75 | 2020 | FIDE Online Olympiad | C41 Philidor Defense |
| 25. Thomas Saah vs J L Marckens |
| 1-0 | 18 | 2020 | FIDE Online Olympiad | B12 Caro-Kann Defense |
Kibitzing
