Game |
| Result | Moves |
Year | Event/Locale | Opening |
1. S Bernstein vs H Seidman |
| ½-½ | 44 | 1939 | Marshall CC Championship | D30 Queen's Gambit Declined |
2. H Seidman vs Santasiere |
  | 1-0 | 24 | 1939 | New York | B29 Sicilian, Nimzovich-Rubinstein |
3. Yanofsky vs H Seidman |
| 0-1 | 45 | 1939 | 40th ACF Congress. Prelim 2 | B73 Sicilian, Dragon, Classical |
4. H Seidman vs Fine |
| ½-½ | 15 | 1939 | ACF Congress (Prelim 2) | A34 English, Symmetrical |
5. H Seidman vs Fine |
 | 0-1 | 37 | 1939 | ACF Congress-Final | D41 Queen's Gambit Declined, Semi-Tarrasch |
6. H Seidman vs G Hellman |
 | 0-1 | 23 | 1939 | ACF Congress-Final | D38 Queen's Gambit Declined, Ragozin Variation |
7. H Seidman vs Reshevsky |
 | 0-1 | 32 | 1939 | ACF Congress-Final | A03 Bird's Opening |
8. Reshevsky vs H Seidman |
| ½-½ | 65 | 1940 | United States Championship | E44 Nimzo-Indian, Fischer Variation, 5.Ne2 |
9. H Seidman vs W Adams |
 | 1-0 | 35 | 1940 | United States Championship | C86 Ruy Lopez, Worrall Attack |
10. Kashdan vs H Seidman |
| 1-0 | 24 | 1940 | United States Championship | D78 Neo-Grunfeld, 6.O-O c6 |
11. H Seidman vs A Pinkus |
 | 0-1 | 43 | 1940 | United States Championship | C53 Giuoco Piano |
12. F Reinfeld vs H Seidman |
| ½-½ | 29 | 1940 | United States Championship | C83 Ruy Lopez, Open |
13. H Seidman vs Kupchik |
| 0-1 | 24 | 1940 | United States Championship | B14 Caro-Kann, Panov-Botvinnik Attack |
14. Fine vs H Seidman |
 | 1-0 | 37 | 1940 | United States Championship | E17 Queen's Indian |
15. H Seidman vs A Simonson |
| 0-1 | 36 | 1940 | United States Championship | C41 Philidor Defense |
16. P R Geffe vs H Seidman |
| 0-1 | 39 | 1940 | United States Championship | B72 Sicilian, Dragon |
17. H Seidman vs M Green |
| ½-½ | 28 | 1940 | United States Championship | E33 Nimzo-Indian, Classical |
18. Denker vs H Seidman |
| 1-0 | 26 | 1940 | United States Championship | E24 Nimzo-Indian, Samisch |
19. H Seidman vs S Bernstein |
| 1-0 | 38 | 1940 | United States Championship | B58 Sicilian |
20. Shainswit vs H Seidman |
| ½-½ | 27 | 1940 | United States Championship | E17 Queen's Indian |
21. H Seidman vs G Littman |
 | 1-0 | 46 | 1940 | United States Championship | C14 French, Classical |
22. M L Hanauer vs H Seidman |
| ½-½ | 37 | 1940 | United States Championship | E23 Nimzo-Indian, Spielmann |
23. H Seidman vs D Polland |
| ½-½ | 20 | 1940 | United States Championship | C78 Ruy Lopez |
24. H Seidman vs J F Donovan |
| 0-1 | 58 | 1940 | Ventnor City | B72 Sicilian, Dragon |
25. L W Stephens vs H Seidman |
| 0-1 | 30 | 1940 | Ventnor City | A45 Queen's Pawn Game |