| Game |
| Result | Moves |
Year | Event/Locale | Opening |
| 26. S Mlotkowski vs L Isaacs |
| 1-0 | 39 | 1928 | 2nd NCF Congress | C30 King's Gambit Declined |
| 27. B Jensen vs L Isaacs |
| 0-1 | 30 | 1929 | Hamilton CC-t Chicago | E60 King's Indian Defense |
| 28. M C Palmer vs L Isaacs |
| 0-1 | 47 | 1930 | 31st Western Championship | D37 Queen's Gambit Declined |
| 29. L Isaacs vs E Michelsen |
| 1-0 | 23 | 1930 | 31st Western Championship | B56 Sicilian |
| 30. S Factor vs L Isaacs |
 | 1-0 | 30 | 1937 | Chicago Championship | A52 Budapest Gambit |
| 31. E Michelsen vs L Isaacs |
 | 0-1 | 38 | 1942 | Chicago City Championship | C53 Giuoco Piano |
| 32. L Isaacs vs H Steiner |
| 0-1 | 47 | 1944 | USA-ch | B04 Alekhine's Defense, Modern |
| 33. Fine vs L Isaacs |
| 1-0 | 34 | 1944 | USA-ch | D97 Grunfeld, Russian |
| 34. L Isaacs vs G Drexel |
| 0-1 | 57 | 1946 | USA-ch (Cancelled game) | C11 French |
| 35. L Isaacs vs A J Fink |
| 0-1 | 37 | 1946 | USA-ch (Cancelled game) | C77 Ruy Lopez |
| 36. O Ulvestad vs L Isaacs |
| 1-0 | 45 | 1946 | USA-ch (Cancelled game) | C44 King's Pawn Game |
| 37. L Isaacs vs S Kowalski |
| 1-0 | 61 | 1946 | USA-ch (Cancelled game) | B73 Sicilian, Dragon, Classical |
| 38. S Rubinow vs L Isaacs |
| 1-0 | 29 | 1946 | USA-ch (Cancelled game) | D82 Grunfeld, 4.Bf4 |
| 39. L Isaacs vs J Levin |
| 0-1 | 69 | 1946 | USA-ch (Cancelled game) | C77 Ruy Lopez |
| 40. Kashdan vs L Isaacs |
| 1-0 | 46 | 1946 | USA-ch (Cancelled game) | C41 Philidor Defense |
| 41. G Kramer vs L Isaacs |
| 1-0 | 38 | 1946 | USA-ch (Cancelled game) | D97 Grunfeld, Russian |
| 42. A H Hobson vs L Isaacs |
| 0-1 | 36 | 1948 | 49th US Open | C24 Bishop's Opening |
| 43. L Isaacs vs J F Donovan |
| 0-1 | 27 | 1948 | 49th US Open | B73 Sicilian, Dragon, Classical |
| 44. D M Scheffer vs L Isaacs |
| 0-1 | 36 | 1948 | 49th US Open | C41 Philidor Defense |
| 45. L Isaacs vs O Bain |
| 1-0 | 33 | 1948 | 49th US Open | B73 Sicilian, Dragon, Classical |
| 46. C Pilnick vs L Isaacs |
| 1-0 | 40 | 1948 | 49th US Open | C41 Philidor Defense |
| 47. R Kujoth vs L Isaacs |
| 1-0 | 54 | 1948 | 49th US Open | A45 Queen's Pawn Game |
| 48. G Hartleb vs L Isaacs |
| 1-0 | 29 | 1948 | 49th US Open | E33 Nimzo-Indian, Classical |
| 49. G Eastman vs L Isaacs |
| 1-0 | 45 | 1951 | 52nd US Open | C84 Ruy Lopez, Closed |
| 50. L Isaacs vs L T Magee |
| 0-1 | 51 | 1951 | 52nd US Open | C77 Ruy Lopez |
Kibitzing
