[Event "World Championship"] [Site "?"] [Round "5"] [White "Spassky"] [Black "Petrosian"] [Result "1-0"] [ECO "A17"] [Opening "English: Anglo-Indian, 2.Nc3 e6 3.Nf3 d5"] 1. c4 Nf6 2. Nc3 e6 3. Nf3 d5 4. d4 c5 5. cxd5 Nxd5 {The game has transposed into a Semi-Tarrasch Variation of the Queen's Gambit Declined, an opening which can arise via a bewildering variety of move orders, even from the Caro Kann (1.e4 c6)!} 6. e4 Nxc3 7. bxc3 cxd4 8. cxd4 Bb4+ 9. Bd2 Bxd2+ 10. Qxd2 O-O 11. Bc4 Nc6 12. O-O b6 13. Rad1 Bb7 { This is a very typical Semi-Tarrasch position.} 14. Rfe1 Rc8 {A simple gl ance at the a2-g8 diagonal is sufficient to encourage White to build a plan based on undermining the pawn chain f7-e6.} 15. d5 {But this may be premature. If Black plays 15...Na5!, then the bishop will have to retreat, since the sacrificial attempt 16.dxe6 does not work. Petrosian missed this chance.} 15... exd5 16. Bxd5 {This is the correct capture. 16.exd5 would have created a passed pawn, but it would be easily blockaded. And, more important, the light squared bishop now has room to maneuver without having to worry about Nc6- a5.} 16... Na5 17. Qf4 Qc7 18. Qf5 Bxd5 {The pressure was building at f7, so Black trades a piece which is not involved in the defense for an attacking piece, almost always a good idea.} 19. exd5 {With the bishops gone, the passed pawn is somewhat harder to blockade, and Black's knight is definitely offside. 19... Nb7 might have been best here.} 19... Qc2 {Black simply has no right to play so ambitiously when his position is inferior and White can afford to ignore the threat at a2. On the other hand, White has no desire to see the queens off the board, as the lady plays escort to the Pd5} 20. Qf4 Qxa2 21. d6 Rcd8 22. d7 {Spassky has achieved the goal of advancing his pawn to the seventh rank, where it severely restricts the mobility of the Black forces. He now needs a new plan to exploit his advantage, and it will involve infiltration via the c-file} 22... Qc4 23. Qf5 h6 24. Rc1 Qa6 25. Rc7 {The next phase has been accomplished. Now the knight has to get into the act. Again, it is important to consider a seemingly impossible goal. The knight belongs at c6. Although that seems difficult to achieve, it is not.} 25... b5 26. Nd4 Qb6 { 26...b4 27.Qe5! with the threat of Nf5 Nc4} 27. Qc5 Rc8 {Nb7 Black had to do this, as the alternatives fail. 27...b4 28.Re8! Qxd4 29.Rxf8+ Rxf8 30.Rxf8+ Kxf8 31.Qc5+!! Qxc5 32.d8Q+} 28. Nc6 {And the knight reaches the desired square, after which Spassky finishes the game beautifully. Nd6 Nxd8!! Nxf5} 28... Nxc6 1-0