[Event "IBM"]
[Site "Amsterdam"]
[Date "1967.??.??"]
[Round "6"]
[White "Portisch, Lajos"]
[Black "Ree, Hans"]
[Result "1-0"]

1. d4 g6 2. c4 Bg7 3. Nc3 d6 4. e4 Nc6 5. Be3 e5 6. d5 Nce7 7. g4 f5 8. gxf5 gxf5 9. Qh5+ Kf8 10. Bh3 Nf6 11. Qf3 f4 12. Bd2 h5 13. Bxc8 Qxc8 14. O-O-O Bh6 15. Qd3 Rg8 16. Nf3 Rg2 17. Qf1 Rg7 18. Kb1 c5 19. dxc6 bxc6 20. Qe2 c5 21. Nb5 Ne8 22. Bc3 Qe6 23. Rhg1 a6 24. Rxg7 Bxg7 25. Na3 Nc6 26. Nh4 Qg4 27. Nf3 Bf6 28. Rg1 Qh3 29. Qd3 Qe6 30. Qd5 Qxd5 31. cxd5 Nd4 32. Bxd4 cxd4 33. Kc2 Ra7 34. Kd3 Rg7 35. Rxg7 Kxg7 36. Nc2 Kf7 37. Nb4 Nc7 38. Nc6 Ke8 39. a4 Kd7 40. Nd2 Bh4 41. Ke2 Bf6 42. Nc4 Bg7 43. Nb6+ Ke8 44. Nb8 Kd8 45. Kd3 Bf6 46. Nc6+ Ke8 47. f3 Bg7 48. Kc4 Bf6 49. Kb4 Bh4 50. h3 Be1+ 51. Kc4 Bh4 52. Kd3 Bf6 53. Na5 Be7 54. Nb7 Bf8 55. Kc4 Be7 56. Nc8 Kd7 57. Nb6+ Ke8 58. b3 Bf8 59. Kb4 Be7 60. Nc4 Kd7 61. Ka5 Bf8 62. Nb2 Be7 63. Nd3 Bh4 64. Kb6 Nxd5+ 65. exd5 e4 66. fxe4 f3 67. Na5 f2 68. Nxf2 Bxf2 69. Nc4 1-0