[Event "IBM"]
[Site "Amsterdam"]
[Date "1964.07.21"]
[Round "1"]
[White "Larsen, Bent"]
[Black "Donner, Jan Hein"]
[Result "1/2-1/2"]

1. e4 c5 2. Nf3 e6 3. Nc3 a6 4. g3 b5 5. Bg2 Bb7 6. O-O b4 7. Na4 Bxe4 8. d4 cxd4 9. Qxd4 Nf6 10. Be3 Nc6 11. Qd2 Be7 12. Rfd1 d5 13. c4 O-O 14. Rac1 dxc4 15. Nb6 Rb8 16. Qe1 Qc7 17. Nxc4 Qb7 18. Bg5 Bd5 19. Ne3 Rfd8 20. Nxd5 Nxd5 21. Qe4 Rbc8 22. Bf1 h6 23. Bxe7 Ncxe7 24. Bd3 g6 25. Rxc8 Qxc8 26. Ne5 a5 27. Qf3 Rf8 28. h4 Qc7 29. Re1 Kg7 30. h5 g5 31. Ng4 Ng8 32. Re5 Qc1+ 33. Kg2 Qxb2 34. Rxd5 exd5 35. Qf5 Re8 36. Nxh6 Nxh6 37. Qxg5+ Kf8 38. Qxh6+ Qg7 39. Qb6 Qe5 40. Qxa5 Qd4 41. Qb5 Re6 42. Bf5 Rf6 43. g4 Kg7 44. Qb8 Rh6 45. Qh2 Rf6 46. Qg3 Kf8 47. Qb8+ Kg7 48. Qg3 1/2-1/2