[Event "Interzonal-09a"]
[Site "Leningrad"]
[Date "1973.06.07"]
[Round "4"]
[White "Karpov, Anatoly"]
[Black "Kortschnoj, Viktor Lvovich"]
[Result "1/2-1/2"]

1. e4 d6 2. d4 Nf6 3. Nc3 g6 4. Nf3 Bg7 5. Be2 O-O 6. O-O Nc6 7. d5 Nb8 8. h3 c6 9. a4 a5 10. Bg5 Bd7 11. Re1 Na6 12. dxc6 Bxc6 13. Bb5 Nb4 14. Qe2 h6 15. Bf4 e5 16. Bh2 Rc8 17. Rad1 Qe7 18. Rd2 h5 1/2-1/2