| Game |
| Result | Moves |
Year | Event/Locale | Opening |
| 26. Gruenfeld vs H Mattison |
| 1-0 | 47 | 1925 | Debrecen | A53 Old Indian |
| 27. H Mattison vs Tartakower |
  | 0-1 | 25 | 1925 | Debrecen | A50 Queen's Pawn Game |
| 28. L Steiner vs H Mattison |
| 0-1 | 38 | 1925 | Debrecen | C42 Petrov Defense |
| 29. Kmoch vs H Mattison |
| 1-0 | 62 | 1925 | Debrecen | D30 Queen's Gambit Declined |
| 30. H Mattison vs D Przepiorka |
| 1-0 | 70 | 1925 | Debrecen | C46 Three Knights |
| 31. K Havasi vs H Mattison |
| 1-0 | 40 | 1925 | Debrecen | A50 Queen's Pawn Game |
| 32. H Mattison vs A Vajda |
| 0-1 | 44 | 1925 | Debrecen | A45 Queen's Pawn Game |
| 33. L Asztalos vs H Mattison |
| ½-½ | 19 | 1925 | Debrecen | D14 Queen's Gambit Declined Slav, Exchange Variation |
| 34. H Mattison vs V Vukovic |
| 0-1 | 20 | 1925 | Debrecen | C13 French |
| 35. H Mattison vs R Millers |
| 1-0 | 14 | 1926 | Koenigsberg | B20 Sicilian |
| 36. H Mattison vs Petrov |
| ½-½ | 44 | 1926 | Incognito Match Riga Ch.Club - Latvian Univ. | B44 Sicilian |
| 37. Kmoch vs H Mattison |
| ½-½ | 15 | 1926 | Budapest 1st FIDE Masters | D11 Queen's Gambit Declined Slav |
| 38. Znosko-Borovsky vs H Mattison |
| 1-0 | 42 | 1926 | Budapest 1st FIDE Masters | D46 Queen's Gambit Declined Semi-Slav |
| 39. H Mattison vs A Vajda |
| 0-1 | 58 | 1926 | Budapest 1st FIDE Masters | C12 French, McCutcheon |
| 40. L Prokes vs H Mattison |
| ½-½ | 21 | 1926 | Budapest 1st FIDE Masters | C54 Giuoco Piano |
| 41. H Mattison vs S Takacs |
| ½-½ | 19 | 1926 | Budapest 1st FIDE Masters | D43 Queen's Gambit Declined Semi-Slav |
| 42. H Mattison vs Tartakower |
| 1-0 | 29 | 1926 | Budapest 1st FIDE Masters | D20 Queen's Gambit Accepted |
| 43. G Nagy vs H Mattison |
| 0-1 | 15 | 1926 | Budapest 1st FIDE Masters | B13 Caro-Kann, Exchange |
| 44. H Mattison vs Reti |
| 0-1 | 26 | 1926 | Budapest 1st FIDE Masters | B88 Sicilian, Fischer-Sozin Attack |
| 45. Colle vs H Mattison |
| ½-½ | 17 | 1926 | Budapest 1st FIDE Masters | A46 Queen's Pawn Game |
| 46. K Havasi vs H Mattison |
| ½-½ | 15 | 1926 | Budapest 1st FIDE Masters | E00 Queen's Pawn Game |
| 47. M Monticelli vs H Mattison |
| 1-0 | 39 | 1926 | Budapest 1st FIDE Masters | E15 Queen's Indian |
| 48. H Mattison vs Yates |
| 1-0 | 15 | 1926 | Budapest 1st FIDE Masters | E12 Queen's Indian |
| 49. E Steiner vs H Mattison |
| 1-0 | 15 | 1926 | Budapest 1st FIDE Masters | C70 Ruy Lopez |
| 50. H Mattison vs Gruenfeld |
| 1-0 | 39 | 1926 | Budapest 1st FIDE Masters | A07 King's Indian Attack |
Kibitzing
