[Event "Mar del Plata"] [Site "Mar del Plata"] [Round "0"] [White "Najdorf"] [Black "Stahlberg"] [Result "0-1"] [ECO "A46"] [Opening "Indian: 2.Nf3"] {The significance of Black's support point at d5} 1. d4 Nf6 2. Nf3 d5 3. c4 e6 4. Nc3 Be7 5. Bg5 Nbd7 6. e3 O-O 7. Rc1 c6 8. Bd3 dxc4 9. Bxc4 Nd5 10. Bxe7 Qxe7 11. O-O Nxc3 12. Rxc3 e5 13. Bb3 e4 14. Nd2 Nf6 {This position is nearly the same as ther previous, except White has played Bb3 instead of Qb1. This little difference clearly favours Black, since White must spend a tempo to unblock his b-pawn. Black's advanced pawn on e4 is more in place here than in the previous example, and theory has not yet quite overcome the tactical problems produced by this pawn} 15. Qc2 Bg4 $1 { The best counter to Rc5-e5 winning the e-pawn. Black now threatens Be2-d3} 16. Re1 $2 (16. Rc1 Be2 17. Bc4) 16... Kh8 17. a3 Rae8 18. Nf1 $2 { the Knight is no better here than it was on d2} (18. Ba2 -- 19. b4 { more purposeful}) 18... Be6 19. Bxe6 Qxe6 20. b4 Nd5 {An important success for Black. The occupation of this support point enables him to work up a powerful offensive on the Kingside} 21. Rc5 a6 22. Ng3 (22. Rb1 f5 23. a4 f4 {no time fo r White thematics. The Black attack is a long way towards its consummation, but for that matter the move played is not a lot better}) 22... f5 23. Qd2 Qh6 $1 24. a4 (24. f4 {If White tries to parry the threat to open the c-file, Black opens the g-file ... the purpose of ... Qh6} 24... g5) 24... f4 25. exf4 (25. Nf1 f3 26. Ng3 Qh4) 25... Nxf4 26. Re3 Nd5 27. Re2 Qxd2 28. Rxd2 e3 $1 { Now both Rooks have open files} (28... Nxb4) 29. fxe3 Rxe3 30. Rc1 Nxb4 31. Nf1 Ra3 {This horizontal activity of the Rooks once they control an open file, has already come to our notice} 32. Re1 Kg8 33. Re7 b6 34. h4 Ra1 35. Rf2 Rxa4 36. Rxf8+ Kxf8 37. Rb7 Nd5 38. Ng3 Rxd4 39. Nf5 Re4 $1 40. Nd6 Re6 41. Rf7+ Kg8 42. Rd7 h6 43. Nf5 Rf6 0-1