[Event "Birmingham U20"]
[Site "Birmingham"]
[Date "1950.04.06"]
[Round "?"]
[White "Sieben, Ivan"]
[Black "Oosterhuis, H."]
[Result "1-0"]
[ECO "C14"]
[PlyCount "59"]
[EventDate "1950.04.03"]
[EventType "swiss"]
[EventRounds "11"]
[EventCountry "ENG"]
[SourceTitle "EXT 2020"]
[Source "ChessBase"]
[SourceDate "2019.10.17"]
[SourceVersion "1"]
[SourceVersionDate "2019.10.17"]
[SourceQuality "1"]

1. e4 e6 2. d4 d5 3. Nc3 Nf6 4. Bg5 Be7 5. e5 Nfd7 6. h4 a6 7. Qd2 h6 8. Bxe7 Qxe7 9. f4 c5 10. Nf3 Nc6 11. dxc5 Qxc5 12. 0-0-0 Ne7 13. g4 b5 14. a3 Bb7 15. Ne4 Qc7 16. Nd6+ Kf8 17. Nd4 Nb6 18. f5 exf5 19. N4xf5 Nxf5 20. gxf5 Rd8 21. Qb4 Kg8 22. Rg1 Rh7 23. Bd3 Nc4 24. Nxb7 Qxb7 25. Bxc4 Qc7 26. Bxd5 Qxe5 27. Bxf7+ Kxf7 28. Qb3+ Ke7 29. Rge1 Rxd1+ 30. Kxd1 1-0

[Event "Birmingham U20"]
[Site "Birmingham"]
[Date "1950.04.03"]
[Round "?"]
[White "Van Bastelaere, Gaston"]
[Black "Sieben, Ivan"]
[Result "1/2-1/2"]
[ECO "B45"]
[PlyCount "100"]
[EventDate "1950.04.03"]
[EventType "swiss"]
[EventRounds "11"]
[EventCountry "ENG"]
[SourceTitle "EXT 2020"]
[Source "ChessBase"]
[SourceDate "2019.10.17"]
[SourceVersion "1"]
[SourceVersionDate "2019.10.17"]
[SourceQuality "1"]

1. e4 c5 2. Nf3 Nc6 3. d4 cxd4 4. Nxd4 Nf6 5. Nc3 e6 6. g3 Bb4 7. Bg2 Qa5 8. 0-0 Bxc3 9. bxc3 Qxc3 10. Nb5 Qxa1 11. Nc7+ Kd8 12. Qd6 Qe5 13. Qxe5 Nxe5 14. Nxa8 Nh5 15. f4 Nc6 16. Bb2 b6 17. e5 g6 18. Bxc6 dxc6 19. Rd1+ Bd7 20. Ba3 c5 21. Rd6 Kc8 22. Nxb6+ axb6 23. Rxb6 Ba4 24. Ra6 Be8 25. Bxc5 Rg8 26. a4 f6 27. a5 fxe5 28. fxe5 Ng7 29. Ra7 Bc6 30. a6 h5 31. Re7 Bd5 32. a7 g5 33. Bb6 Ne8 34. c4 Ba8 35. Rxe6 h4 36. g4 Kd7 37. Rh6 Rg7 38. c5 Re7 39. c6+ Kc8 40. Bd4 Nc7 41. Rh8+ Re8 42. Rh6 Ne6 43. Bb6 Bxc6 44. Rg6 Be4 45. Be3 Kb7 46. Rf6 Nd8 47. Rb6+ Kc7 48. Rb8 Kd7 49. a8Q Bxa8 50. Rxa8 Rxe5 1/2-1/2

