| Game |
| Result | Moves |
Year | Event/Locale | Opening |
| 1. K Ruben vs A Nimzowitsch |
| ½-½ | 44 | 1927 | Copenhagen Masters Politiken | E20 Nimzo-Indian |
| 2. K Ruben vs G Stoltz |
 | ½-½ | 42 | 1927 | London Olympiad | D15 Queen's Gambit Declined Slav |
| 3. H Wagner vs K Ruben |
| ½-½ | 65 | 1927 | London Olympiad | A46 Queen's Pawn Game |
| 4. K Ruben vs H Grob |
| ½-½ | 42 | 1927 | London Olympiad | E60 King's Indian Defense |
| 5. J Terho vs K Ruben |
| 0-1 | 27 | 1927 | London Olympiad | C01 French, Exchange |
| 6. K Ruben vs J W te Kolste |
| 0-1 | 36 | 1927 | London Olympiad | E62 King's Indian, Fianchetto |
| 7. K Ruben vs Kmoch |
| 1-0 | 30 | 1927 | London Olympiad | E12 Queen's Indian |
| 8. K Ruben vs L Palau |
| 1-0 | 31 | 1927 | London Olympiad | D37 Queen's Gambit Declined |
| 9. A Pokorny vs K Ruben |
| 0-1 | 36 | 1927 | London Olympiad | C12 French, McCutcheon |
| 10. Koltanowski vs K Ruben |
| 1-0 | 49 | 1927 | London Olympiad | D61 Queen's Gambit Declined, Orthodox, Rubinstein Attack |
| 11. K Ruben vs J Rejfir |
| 0-1 | 40 | 1928 | The Hague Olympiad | E12 Queen's Indian |
| 12. C H Maderna vs K Ruben |
| 0-1 | 39 | 1928 | The Hague Olympiad | E32 Nimzo-Indian, Classical |
| 13. K Ruben vs D Marotti |
| 1-0 | 39 | 1928 | The Hague Olympiad | D48 Queen's Gambit Declined Semi-Slav, Meran |
| 14. K Ruben vs A Taube |
| 1-0 | 30 | 1928 | The Hague Olympiad | D63 Queen's Gambit Declined, Orthodox Defense |
| 15. Alekhine vs K Ruben |
| 0-1 | 32 | 1930 | Clock simul, 10b | C79 Ruy Lopez, Steinitz Defense Deferred |
| 16. K Ruben vs H Weenink |
| 1-0 | 26 | 1930 | Hamburg Olympiad | D18 Queen's Gambit Declined Slav, Dutch |
| 17. J Lokvenc vs K Ruben |
| 1-0 | 59 | 1930 | Hamburg Olympiad | A13 English |
| 18. K Ruben vs S Khan |
| 1-0 | 74 | 1930 | Hamburg Olympiad | E15 Queen's Indian |
| 19. J Rejfir vs K Ruben |
| 0-1 | 41 | 1930 | Hamburg Olympiad | E32 Nimzo-Indian, Classical |
| 20. K Ruben vs C Lafora |
| ½-½ | 53 | 1930 | Hamburg Olympiad | E12 Queen's Indian |
| 21. J A Anderson vs K Ruben |
| 0-1 | 47 | 1930 | Hamburg Olympiad | E23 Nimzo-Indian, Spielmann |
| 22. K Ruben vs K Richter |
| 0-1 | 27 | 1930 | Hamburg Olympiad | A52 Budapest Gambit |
| 23. K Ruben vs G Thomas |
| 0-1 | 20 | 1931 | Prague Olympiad | E77 King's Indian |
| 24. K Richter vs K Ruben |
| 1-0 | 39 | 1931 | Prague Olympiad | A46 Queen's Pawn Game |
| 25. K Ruben vs L Steiner |
| 0-1 | 18 | 1931 | Prague Olympiad | D02 Queen's Pawn Game |
Kibitzing
