| Game |
| Result | Moves |
Year | Event/Locale | Opening |
| 51. J Nielsen vs T Popa |
| 1-0 | 28 | 1936 | non-FIDE Munich Olympiad | E16 Queen's Indian |
| 52. J Pelikan vs J Nielsen |
| 0-1 | 25 | 1936 | non-FIDE Munich Olympiad | A03 Bird's Opening |
| 53. J Nielsen vs E Dyckhoff |
| ½-½ | 44 | 1938 | 1st European cc Olympiad 1937/38 | D34 Queen's Gambit Declined, Tarrasch |
| 54. Gruenfeld vs J Nielsen |
| ½-½ | 35 | 1938 | 1st European cc Olympiad 1937/38 | D34 Queen's Gambit Declined, Tarrasch |
| 55. B Nielsen vs J Nielsen |
| 1-0 | 21 | 1939 | DEN-ch | D26 Queen's Gambit Accepted |
| 56. J Nielsen vs C Poulsen |
| 0-1 | 43 | 1939 | DEN-ch | D97 Grunfeld, Russian |
| 57. P Hage vs J Nielsen |
| ½-½ | 21 | 1939 | DEN-ch | C49 Four Knights |
| 58. J Enevoldsen vs J Nielsen |
| 1-0 | 62 | 1939 | DEN-ch | D50 Queen's Gambit Declined |
| 59. P Hage vs J Nielsen |
 | 1-0 | 54 | 1941 | DEN-ch | C42 Petrov Defense |
| 60. J Nielsen vs C Poulsen |
| 1-0 | 29 | 1942 | DEN-ch | D82 Grunfeld, 4.Bf4 |
| 61. B Nielsen vs J Nielsen |
| 0-1 | 23 | 1942 | DEN-ch | A30 English, Symmetrical |
| 62. C Poulsen vs J Nielsen |
| 1-0 | 38 | 1942 | DEN-ch | C65 Ruy Lopez, Berlin Defense |
| 63. J Enevoldsen vs J Nielsen |
| 1-0 | 25 | 1943 | DEN-ch | C65 Ruy Lopez, Berlin Defense |
| 64. J Nielsen vs B Nielsen |
| 1-0 | 32 | 1943 | DEN-ch | B03 Alekhine's Defense |
| 65. J Nielsen vs B Nielsen |
| 0-1 | 56 | 1944 | DEN-ch | C55 Two Knights Defense |
| 66. B Nielsen vs J Nielsen |
| 1-0 | 51 | 1945 | DEN-ch | D34 Queen's Gambit Declined, Tarrasch |
| 67. P Hage vs J Nielsen |
| 1-0 | 37 | 1946 | DEN-ch | C49 Four Knights |
| 68. E Jonsson vs J Nielsen |
| 1-0 | 46 | 1946 | Nordic Congress, Copenhagen | C64 Ruy Lopez, Classical |
| 69. J Nielsen vs C Poulsen |
| 0-1 | 32 | 1947 | DEN-ch | E16 Queen's Indian |
| 70. T Nielsen vs J Nielsen |
| 0-1 | 40 | 1947 | Aalborg | C34 King's Gambit Accepted |
| 71. T Sorensen vs J Nielsen |
| 0-1 | 12 | 1947 | Aalborg | C58 Two Knights |
| 72. J Nielsen vs A Christensen |
 | ½-½ | 42 | 1947 | Aalborg | D92 Grunfeld, 5.Bf4 |
| 73. C Poulsen vs J Nielsen |
| 1-0 | 20 | 1947 | Aalborg | C64 Ruy Lopez, Classical |
| 74. J Nielsen vs B H Wood |
| 0-1 | 38 | 1947 | Aalborg | E94 King's Indian, Orthodox |
| 75. J Nielsen vs G Stoltz |
| 0-1 | 45 | 1947 | Aalborg | D32 Queen's Gambit Declined, Tarrasch |
Kibitzing
