[Event "IBM"]
[Site "Amsterdam"]
[Date "1963.??.??"]
[Round "1"]
[White "Donner, Jan Hein"]
[Black "Udovcic, Mijo"]
[Result "1/2-1/2"]

1. d4 Nf6 2. c4 g6 3. g3 Bg7 4. Bg2 O-O 5. Nc3 d6 6. Nf3 c5 7. d5 a6 8. a4 e6 9. dxe6 Bxe6 10. Bf4 Nc6 11. Bxd6 Re8 12. Bxc5 Qa5 13. Be3 Ng4 14. Bd2 Bxc4 15. O-O Qb6 16. a5 Qc5 17. Qc1 Rad8 18. h3 Nge5 19. Be3 Nxf3+ 20. Bxf3 Nd4 21. Kg2 Qe7 22. Bxd4 Bxd4 23. Re1 Bb3 24. e3 Bg7 1/2-1/2