| New York 1939 (2) |
Marshall Club - Rice Progressive Club Match |
| | | | | | |
|
Seidman, H. - Treistman, M. |
1 - 0 |
| | | |
| New York 1939 (3) |
Manhattan Club - Marshall Club Match |
| | | | | | |
|
Seidman, H. - Adams, W.W. |
0.5 - 0.5 |
| | | |
| New York 1939 (5) |
40th American Chess Federation Congress - Preliminary Section 2 |
4 | / | 6 |
| | | |
| New York 1939 (8) |
40th American Chess Federation Congress - Final |
5 | / | 10 |
| | | |
| New York 1939 (13) |
22nd Marshall Club Championship |
5 | / | 10 |
| | | |
| New York 1940 (3) |
23rd Marshall Club Championship |
10.5 | / | 16 |
| | | |
| New York 1940 (7) |
3rd U.S.A. Championship - Preliminary Section C |
7 | / | 8 |
| | | |
| New York 1940 (8) |
3rd U.S.A. Championship - Final |
7 | / | 16 |
| | | |
| New York 1941 (3) |
24th Marshall Club Championship |
10.5 | / | 15 |
| | | |
| New York 1941 (4) |
Marshall Club - Manhattan Club Match |
| | | | | | |
|
Seidman, H. - Willman, R. |
0.5 - 0.5 |
| | | |
| Hamilton, New York 1941 (1) |
63rd New York State Chess Association Championship - Masters |
4 | / | 10 |
| | | |
| New York 1942 (1) |
Marshall Club Championship |
11 | / | 12 |
| | | |
| New York 1942 (3) |
Marshall Club - Manhattan Club Match |
| | | | | | |
|
Seidman, H. - Horowitz, I.A. |
0 - 1 |
| | | |
| New York 1942 (4) |
4th USA Chammpionship - Final |
7 | / | 15 |
| | | |
| New York 1944 (2) |
Marshall Club - Manhattan Club Match |
| | | | | | |
|
Seidman, H. - Moskowitz, J. |
1 - 0 |
| | | |
| New York 1944 (4) |
27th Marshall Club Championship |
12.5 | / | 13 |
| | | |
| Hollywood 1945 |
Pan American Tournament |
3 | / | 10 |
| | | |
| Moscow and New York 1945 |
USSR - USA Radio Match |
| | | | | | |
|
Seidman, H. - Ragozin, V.V. |
0 - 2 |
| | | |
| New York 1946 (2) |
Manhattan Club - Brooklyn Club Match |
| | | | | | |
|
Seidman, H. - Horowitz, I.A. |
0 - 1 |
| | | |
| New York 1946 (3) |
Metropolitan Championship |
5 | / | 9 |
| | | |
| Pittsburgh 1946 |
47th U.S.A. Open Championship - Final |
7 | / | 9 |
| | | |
| New York 1946 (6) |
29th Marshall Club Championship |
14 | / | 16 |
| | | |
