[Event "Olympiad-19 Preliminaries A"]
[Site "Siegen"]
[Date "1970.09.08"]
[Round "4"]
[White "Vasquez, Julio E"]
[Black "Yabra, Frederico"]
[Result "1/2-1/2"]

1. d4 Nf6 2. c4 e5 3. dxe5 Ne4 4. Nf3 Bb4+ 5. Nbd2 Nc6 6. a3 Bxd2+ 7. Bxd2 Qe7 8. Bf4 g5 9. Qd5 gxf4 10. Qxe4 d6 11. Qxf4 dxe5 12. Qg5 e4 13. Qg7 Rf8 14. Ng5 Bf5 15. Nxh7 Bxh7 16. Qxh7 O-O-O 17. g3 Nd4 18. O-O-O Qe5 19. Bg2 f5 20. e3 Nb3+ 21. Kc2 Nd2 22. Bh3 Kb8 23. Bf1 Rd6 24. Be2 Rfd8 25. Qh4 Qa5 26. Qe7 a6 27. h4 Qa4+ 28. Kc1 Qb3 29. h5 Qa2 30. Kc2 Qb3+ 31. Kc1 R8d7 32. Qe8+ Ka7 33. Qe5 Qa2 34. Kc2 Qb3+ 1/2-1/2