[Event "US Open-62"]
[Site "San Francisco"]
[Date "1961.08.24"]
[Round "10"]
[White "Groenig, David"]
[Black "Sutherland, Don C"]
[Result "1/2-1/2"]
[ECO "A97"]
[PlyCount "67"]
[EventDate "1961.08.14"]
[EventType "swiss"]
[EventRounds "12"]
[EventCountry "USA"]
[SourceTitle "EXT 2020"]
[Source "ChessBase"]
[SourceDate "2019.10.17"]
[SourceVersion "1"]
[SourceVersionDate "2019.10.17"]
[SourceQuality "1"]

1. Nf3 f5 2. d4 e6 3. g3 Nf6 4. Bg2 Be7 5. c4 d6 6. Nc3 0-0 7. 0-0 Qe8 8. b4 Nbd7 9. Qd3 Nh5 10. Bd2 c6 11. e4 f4 12. Rab1 g5 13. e5 d5 14. g4 dxc4 15. Qxc4 Nb6 16. Qd3 Ng7 17. Ne1 h5 18. h3 Qf7 19. Be4 Nf5 20. gxf5 exf5 21. Bg2 Be6 22. d5 cxd5 23. Qd4 Rac8 24. Ne2 Rc4 25. Qb2 f3 26. Nxf3 f4 27. Nfd4 f3 28. Nxf3 Bxh3 29. Nxg5 Bxg5 30. Bxh3 Qg6 31. Bxg5 Qxg5+ 32. Kh2 Rf3 33. Ng1 Qf4+ 34. Kg2 1/2-1/2

[Event "US Open-62"]
[Site "San Francisco"]
[Date "1961.08.21"]
[Round "7"]
[White "Dahlberg, Ivars A"]
[Black "Groenig, David"]
[Result "1-0"]
[ECO "A51"]
[PlyCount "51"]
[EventDate "1961.08.14"]
[EventType "swiss"]
[EventRounds "12"]
[EventCountry "USA"]
[SourceTitle "EXT 2020"]
[Source "ChessBase"]
[SourceDate "2019.10.17"]
[SourceVersion "1"]
[SourceVersionDate "2019.10.17"]
[SourceQuality "1"]

1. d4 Nf6 2. c4 e5 3. dxe5 Ne4 4. a3 d6 5. Qc2 Bf5 6. Nc3 Nxf2 7. Qxf5 Nxh1 8. e6 fxe6 9. Qxe6+ Be7 10. Nf3 Qd7 11. Qxd7+ Kxd7 12. g3 c6 13. Bh3+ Kc7 14. Bg2 Nxg3 15. hxg3 Nd7 16. Bf4 h6 17. 0-0-0 g5 18. Bd2 Rae8 19. Nd4 Bf6 20. Nf5 Re5 21. Rf1 Ree8 22. Ne4 Be5 23. Rh1 Re6 24. Bf3 a6 25. Kc2 Nf6 26. Nxg5 1-0

[Event "US Open-62"]
[Site "San Francisco"]
[Date "1961.08.20"]
[Round "6"]
[White "Groenig, David"]
[Black "Colon Romero, Miguel"]
[Result "1-0"]
[ECO "E19"]
[PlyCount "81"]
[EventDate "1961.08.14"]
[EventType "swiss"]
[EventRounds "12"]
[EventCountry "USA"]
[SourceTitle "EXT 2020"]
[Source "ChessBase"]
[SourceDate "2019.10.17"]
[SourceVersion "1"]
[SourceVersionDate "2019.10.17"]
[SourceQuality "1"]

1. d4 e6 2. Nf3 f5 3. g3 b6 4. Bg2 Bb7 5. 0-0 Nf6 6. c4 Be7 7. Nc3 Ne4 8. Qc2 Nxc3 9. bxc3 0-0 10. a4 Be4 11. Qd1 a5 12. Ne1 Bxg2 13. Nxg2 Qe8 14. Qd3 g5 15. e4 Qg6 16. exf5 exf5 17. f4 g4 18. Ne3 d6 19. Re1 Bd8 20. Bd2 c6 21. c5 bxc5 22. dxc5 dxc5 23. Rab1 Qf7 24. Rb2 Nd7 25. Reb1 c4 26. Qd6 Qe7 27. Qxc6 Bb6 28. Qxc4+ Kh8 29. Rxb6 Nxb6 30. Rxb6 Rad8 31. Bc1 Rfe8 32. Rb5 Qa7 33. Qc5 Qa8 34. Qxf5 Qc6 35. c4 Rxe3 36. Bb2+ Kg8 37. Qg5+ Kf7 38. Qxd8 Re1+ 39. Kf2 Re7 40. Rf5+ Kg6 41. Rg5+ 1-0

