[Event "IBM"]
[Site "Amsterdam"]
[Date "1970.07.25"]
[Round "10"]
[White "Donner, Jan Hein"]
[Black "Hartoch, Robert G"]
[Result "1/2-1/2"]

1. d4 Nf6 2. c4 c5 3. d5 d6 4. Nc3 g6 5. e4 Bg7 6. Be2 O-O 7. Bg5 a6 8. a4 Qa5 9. Bd2 e6 10. Nf3 Qc7 11. O-O exd5 12. cxd5 Re8 13. Qc2 Bg4 14. Rfe1 Nbd7 15. a5 c4 16. Be3 Nc5 17. Nd2 Bxe2 18. Rxe2 Ncd7 19. h3 Re7 20. Qa4 Rc8 21. Rc1 Nc5 22. Qxc4 Nfd7 23. Rc2 Qxa5 24. b4 Qa1+ 25. Ndb1 Nb6 26. Qa2 Qxa2 27. Nxa2 Nca4 28. Rxc8+ Nxc8 29. Rc2 Ncb6 30. Nd2 f5 31. Bf4 Rd7 32. f3 fxe4 33. fxe4 Nb2 34. Nc1 N6a4 35. Rc8+ Kf7 36. Nf3 h6 37. Ne2 Nb6 38. Rc2 Nd3 39. Bd2 Re7 40. Ng3 Re8 41. Kf1 Rc8 42. Rxc8 Nxc8 43. Ke2 Nb2 44. Nf1 Nb6 45. Ne3 N6c4 46. Nxc4 Nxc4 47. Bf4 1/2-1/2