[Event "IBM"]
[Site "Amsterdam"]
[Date "1961.??.??"]
[Round "11"]
[White "Donner, Jan Hein"]
[Black "Enevoldsen, Jens"]
[Result "1/2-1/2"]

1. d4 Nf6 2. c4 e6 3. Nc3 c5 4. d5 exd5 5. cxd5 d6 6. Nf3 g6 7. Nd2 Bg7 8. Nc4 O-O 9. Bf4 Ne8 10. e3 Na6 11. Be2 Nac7 12. a4 b6 13. O-O Ba6 14. Qd2 Bxc4 15. Bxc4 a6 16. e4 Rb8 17. Qe2 b5 18. axb5 axb5 19. Nxb5 Nxb5 20. Bxb5 Nc7 21. Bc6 Rxb2 22. Qe3 Bd4 23. Qg3 Ne8 24. Rae1 Qa5 25. Be3 Bxe3 26. Rxe3 Qc7 27. f4 f6 28. h4 Ng7 29. f5 c4 30. Kh2 Nh5 31. Qg4 Kg7 32. Rc3 Qe7 33. Rxc4 Qe5+ 34. Kg1 Ng3 35. Re1 Nxf5 36. Ba4 Qg3 37. Qxg3 Nxg3 38. Bd1 Re8 39. Kh2 Nf5 40. Kh3 Re7 41. Bf3 Nh6 42. Rec1 Rb8 43. Rc7 Rb7 44. R7c6 Nf7 45. Kg3 Ra7 46. R1c3 Ra4 47. Rc7 Ra7 48. Rxa7 Rxa7 49. Rc6 Re7 50. Kf4 h5 51. Ra6 g5+ 52. hxg5 fxg5+ 53. Ke3 g4 54. Bd1 Rc7 55. Ba4 h4 56. Kf4 h3 57. gxh3 gxh3 58. Bc6 h2 59. Ra1 Ra7 60. Rh1 Ra2 1/2-1/2