[Event "IBM"]
[Site "Amsterdam"]
[Date "1969.??.??"]
[Round "11"]
[White "Donner, Jan Hein"]
[Black "Hartoch, Robert G"]
[Result "1/2-1/2"]

1. d4 d5 2. c4 e6 3. cxd5 exd5 4. Nc3 Be7 5. Bf4 Nf6 6. e3 O-O 7. Bd3 b6 8. Nge2 c5 9. O-O c4 10. Bc2 Bb7 11. b3 cxb3 12. Bxb3 Nc6 13. Be5 Na5 14. Bxf6 Bxf6 15. Nf4 Nxb3 16. axb3 Qd7 17. b4 a6 18. Qb3 Rfd8 19. Rfc1 Rac8 20. Nd3 h5 21. b5 a5 22. Na4 Qd6 23. Rxc8 Rxc8 24. Rc1 Rxc1+ 25. Nxc1 Bd8 26. Nd3 h4 27. Nc3 g5 28. g3 hxg3 29. hxg3 Kg7 30. Kf1 f6 31. Ke2 Be7 32. Kd2 Qd7 33. Qd1 Qc7 34. Qb3 Qd6 35. Qa2 Kf8 36. Qa1 Qd7 37. Qh1 Kg7 38. Qh5 Bb4 39. f4 Qc7 40. Nxb4 axb4 41. Nd1 Qe7 42. f5 Bc8 43. Qg6+ Kf8 44. Nf2 b3 45. Qh6+ 1/2-1/2