[Event "IBM"]
[Site "Amsterdam"]
[Date "1969.??.??"]
[Round "4"]
[White "Gheorghiu, Florin"]
[Black "Barendregt, Johan"]
[Result "1/2-1/2"]

1. c4 g6 2. Nc3 Bg7 3. d4 d6 4. e4 c5 5. d5 Bxc3+ 6. bxc3 e5 7. h4 h5 8. Bg5 f6 9. Bd2 Nh6 10. Qc1 Nf7 11. Bd3 Qe7 12. Nf3 Nd7 13. Qc2 Nf8 14. Be3 Nh6 15. Nh2 Ng4 16. Nxg4 Bxg4 17. a4 O-O-O 18. a5 Kb8 19. Rb1 Bc8 20. f3 Nh7 1/2-1/2