| Game |
| Result | Moves |
Year | Event/Locale | Opening |
| 26. R Fuchs vs J Kostro |
| 1-0 | 23 | 1958 | Kienbaum | A61 Benoni |
| 27. R G Wade vs J Kostro |
| ½-½ | 30 | 1958 | Munich Olympiad qual-3 | C50 Giuoco Piano |
| 28. N Macleod vs J Kostro |
| 0-1 | 50 | 1958 | Munich Olympiad qual-3 | C35 King's Gambit Accepted, Cunningham |
| 29. J Kostro vs A Tarazi |
| 1-0 | 33 | 1958 | Munich Olympiad qual-3 | B32 Sicilian |
| 30. J Kostro vs W Pietzsch |
 | 1-0 | 21 | 1958 | Munich Olympiad qual-3 | C78 Ruy Lopez |
| 31. J Kostro vs M Borja |
| ½-½ | 62 | 1958 | Munich Olympiad qual-3 | B77 Sicilian, Dragon, Yugoslav Attack |
| 32. I Bilek vs J Kostro |
| ½-½ | 56 | 1958 | Munich Olympiad qual-3 | A13 English |
| 33. P Martin vs J Kostro |
| 1-0 | 48 | 1958 | Munich Olympiad Final-B | E05 Catalan, Open, Classical line |
| 34. J Kostro vs H Kramer |
| ½-½ | 23 | 1958 | Munich Olympiad Final-B | B56 Sicilian |
| 35. J Kostro vs Forintos |
| 0-1 | 27 | 1958 | Munich Olympiad Final-B | B43 Sicilian, Kan, 5.Nc3 |
| 36. J Kostro vs H Koskinen |
| ½-½ | 73 | 1958 | Munich Olympiad Final-B | B16 Caro-Kann, Bronstein-Larsen Variation |
| 37. J Kostro vs A Gudmundsson |
| 1-0 | 28 | 1958 | Munich Olympiad Final-B | B56 Sicilian |
| 38. J Kostro vs G Noradounghian |
| ½-½ | 27 | 1958 | Munich Olympiad Final-B | C75 Ruy Lopez, Modern Steinitz Defense |
| 39. E Pedersen vs J Kostro |
| 1-0 | 25 | 1958 | Munich Olympiad Final-B | C70 Ruy Lopez |
| 40. E Book vs J Kostro |
| 0-1 | 48 | 1959 | Krakow | C97 Ruy Lopez, Closed, Chigorin |
| 41. Korchnoi vs J Kostro |
| ½-½ | 53 | 1959 | Krakow | E59 Nimzo-Indian, 4.e3, Main line |
| 42. J Kostro vs Sliwa |
| 1-0 | 28 | 1959 | Krakow | C12 French, McCutcheon |
| 43. J Kozma vs J Kostro |
| ½-½ | 51 | 1959 | Krakow | A14 English |
| 44. G Mititelu vs J Kostro |
| 1-0 | 56 | 1960 | Budapest Zonal | E16 Queen's Indian |
| 45. J Kostro vs P H Clarke |
| 0-1 | 32 | 1960 | Budapest Zonal | B84 Sicilian, Scheveningen |
| 46. A Prameshuber vs J Kostro |
| 1-0 | 38 | 1960 | Budapest Zonal | A04 Reti Opening |
| 47. J Kostro vs E Ahman |
| 1-0 | 30 | 1960 | Budapest Zonal | B75 Sicilian, Dragon, Yugoslav Attack |
| 48. M Ujtelky vs J Kostro |
| ½-½ | 35 | 1960 | Budapest Zonal | E46 Nimzo-Indian |
| 49. J Kostro vs W Golz |
| 1-0 | 65 | 1960 | Budapest Zonal | C18 French, Winawer |
| 50. M Bertok vs J Kostro |
| ½-½ | 42 | 1960 | Budapest Zonal | E16 Queen's Indian |
Kibitzing
