[Event "IBM"]
[Site "Amsterdam"]
[Date "1971.07.26"]
[Round "11"]
[White "Portisch, Lajos"]
[Black "Bobotsov, Milko Georgiev"]
[Result "1-0"]
1. d4 d5 2. c4 e6 3. Nc3 Be7 4. Nf3 Nf6 5. Bf4 c5 6. dxc5 Na6 7. Bd6 Nxc5 8. Bxe7 Qxe7 9. cxd5 exd5 10. e3 O-O 11. Be2 Nce4 12. Qd4 Nxc3 13. Qxc3 Bg4 14. O-O Rac8 15. Qb3 Rc7 16. Nd4 Bxe2 17. Nxe2 Qe5 18. Rad1 Rd8 19. Rd4 Rcd7 20. Rfd1 Ne4 21. Nf4 Nf6 22. h3 g6 23. Qa4 a6 24. Qb3 Kg7 25. a4 h5 26. Nd3 Qe7 27. a5 Kg8 28. Nf4 Qc5 29. Qd3 Kg7 30. Qxg6+ fxg6 31. Ne6+ Kf7 32. Nxc5 Rc7 33. b4 Re8 34. h4 Re5 35. g3 Rf5 36. Kg2 Re7 37. Nd3 Rc7 38. Nf4 Rc2 39. R1d2 Rxd2 40. Rxd2 g5 41. hxg5 1-0