[Event "IBM"]
[Site "Amsterdam"]
[Date "1968.??.??"]
[Round "4"]
[White "Ree, Hans"]
[Black "Jongsma, Alexander"]
[Result "1/2-1/2"]

1. c4 Nf6 2. g3 c6 3. Bg2 d5 4. Nf3 Bg4 5. b3 e6 6. O-O Nbd7 7. Bb2 Be7 8. d3 O-O 9. Nbd2 a5 10. a3 Re8 11. h3 Bh5 12. Qc2 Bf8 13. e4 dxe4 14. Nxe4 Nxe4 15. dxe4 e5 16. Bc3 Qb6 17. Qb2 f6 18. b4 axb4 19. axb4 c5 20. b5 Bd6 21. Qd2 Bc7 22. Qd5+ Kf8 23. Rfd1 Red8 24. Rxa8 Rxa8 25. Qd3 Kg8 26. Rf1 Nf8 27. Nh4 Rd8 28. Qe3 Bf7 29. Qe2 Qe6 30. Rc1 Qxc4 31. Qxc4 Bxc4 32. Bxe5 Bxe5 33. Rxc4 Rd1+ 34. Bf1 Nd7 35. Nf5 1/2-1/2