[Event "IBM"]
[Site "Amsterdam"]
[Date "1971.07.17"]
[Round "5"]
[White "Ree, Hans"]
[Black "Ivkov, Borislav"]
[Result "1/2-1/2"]

1. e4 e6 2. d4 d5 3. Nc3 Bb4 4. Ne2 dxe4 5. a3 Be7 6. Nxe4 Nf6 7. N2g3 Nbd7 8. Bd3 b6 9. O-O Bb7 10. Re1 O-O 11. Bf4 Nxe4 12. Nxe4 Nf6 13. Nxf6+ Bxf6 14. c3 Rc8 15. Qc2 g6 16. Rad1 Qe7 17. Be4 Bxe4 18. Qxe4 c6 19. Be5 Rfd8 20. Rd3 Bxe5 21. Qxe5 Rd5 22. Qe4 Rcd8 23. Red1 Qd7 24. c4 Rd6 25. h4 h5 26. g3 Qe7 27. Qe5 Qf8 28. R1d2 R8d7 29. Kf1 Qd8 30. Kg1 Qf8 31. Kf1 Rd8 32. Kg1 Qg7 33. Qe4 Qf6 34. Kg2 Qe7 35. Kg1 b5 36. b3 bxc4 37. bxc4 Qb7 38. Qe5 Qa6 39. Qc5 Qb6 40. Qe5 Qa6 41. Qc5 1/2-1/2