| Game |
| Result | Moves |
Year | Event/Locale | Opening |
| 26. G Gruen vs Vladimirov |
| 0-1 | 57 | 1981 | World Youth U26 Team Championship | E15 Queen's Indian |
| 27. G Gruen vs E Schmittdiel |
| 1-0 | 46 | 1981 | NRW-ch | E17 Queen's Indian |
| 28. G Schmidt vs G Gruen |
| 0-1 | 34 | 1981 | NRW-ch | E18 Queen's Indian, Old Main line, 7.Nc3 |
| 29. W Groenegress vs G Gruen |
| ½-½ | 50 | 1981 | NRW-ch | B22 Sicilian, Alapin |
| 30. G Gruen vs S Ingenerf |
| 0-1 | 61 | 1981 | NRW-ch | E69 King's Indian, Fianchetto, Classical Main line |
| 31. A Weiermann vs G Gruen |
| 0-1 | 49 | 1981 | NRW-ch | A00 Uncommon Opening |
| 32. G Gruen vs M Mudersbach |
| 1-0 | 60 | 1981 | NRW-ch | D31 Queen's Gambit Declined |
| 33. W Beckemeyer vs G Gruen |
| 1-0 | 40 | 1981 | NRW-ch | B64 Sicilian, Richter-Rauzer Attack |
| 34. R Lau vs G Gruen |
| 0-1 | 30 | 1981 | NRW-ch | E12 Queen's Indian |
| 35. Hort vs G Gruen |
| 1-0 | 39 | 1983 | Bundesliga 1982/83 | A00 Uncommon Opening |
| 36. G Gruen vs Chandler |
| ½-½ | 51 | 1983 | Bundesliga 1982/83 | D34 Queen's Gambit Declined, Tarrasch |
| 37. G Gruen vs Sosonko |
| ½-½ | 17 | 1983 | Bundesliga 1982/83 | D38 Queen's Gambit Declined, Ragozin Variation |
| 38. G Gruen vs Spassky |
| ½-½ | 22 | 1983 | Bundesliga 1982/83 | E91 King's Indian |
| 39. G Gruen vs P Scheeren |
| ½-½ | 63 | 1983 | EUR-chT (Men) 8th | E15 Queen's Indian |
| 40. G Gruen vs J Ost-Hansen |
| ½-½ | 60 | 1983 | EUR-chT (Men) 8th | E92 King's Indian |
| 41. Romanishin vs G Gruen |
| 1-0 | 38 | 1983 | EUR-chT (Men) 8th | E17 Queen's Indian |
| 42. G Gruen vs M Cebalo |
| ½-½ | 33 | 1983 | EUR-chT (Men) 8th | A70 Benoni, Classical with 7.Nf3 |
| 43. G Gruen vs M Hebden |
| 1-0 | 56 | 1983 | EUR-chT (Men) 8th | E92 King's Indian |
| 44. A Groszpeter vs G Gruen |
| 0-1 | 41 | 1983 | EUR-chT (Men) 8th | E14 Queen's Indian |
| 45. E Ermenkov vs G Gruen |
| 1-0 | 20 | 1983 | EUR-chT (Men) 8th | B03 Alekhine's Defense |
| 46. G Gruen vs R Tibensky |
| 1-0 | 43 | 1984 | Tirnavia-B | A42 Modern Defense, Averbakh System |
| 47. G Gruen vs Lobron |
| ½-½ | 32 | 1984 | Bundesliga 1983/84 | E06 Catalan, Closed, 5.Nf3 |
| 48. W Kruszynski vs G Gruen |
| ½-½ | 42 | 1984 | Hamburg Schachfestival | B05 Alekhine's Defense, Modern |
| 49. T Horvath vs G Gruen |
| 0-1 | 27 | 1984 | Hamburg Schachfestival | B05 Alekhine's Defense, Modern |
| 50. G Gruen vs D Donchev |
| ½-½ | 49 | 1984 | Hamburg Schachfestival | D23 Queen's Gambit Accepted |
Kibitzing
