Tigran, Tigran, burning bright

This year Tigran Petrosian would have celebrated his 90th birthday. The Armenian grandmaster and world champion was noted for the profundity and originality of his strategic concepts, as well as his quasi-invincibility in high level contests. He was certainly my role model when I was a student of chess in my teens, a chess hero to emulate along with Aron Nimzowitsch, Richard Reti, Alexander Alekhine and Mikhail Botvinnik.
 
Petrosian-Gligoric: Zagreb 1965; Grunfeld Defence
 
1 d4 Nf6 2 c4 g6 3 Nc3 d5 4 Nf3 Bg7 5 e3 0-0 6 Bd2 c6 7 Be2 Ne4 8 0-0 Nxd2 9 Qxd2 e6 10 cxd5 exd5 11 b4 In this structure White plans to establish an enduring bind on the queenside. 11 … Nd7 12 b5 Nf6 13 bxc6 bxc6 14 Na4 Bf5 15 Bd3 Ne4 16 Qc2 The c-file is White’s playground. 16 … Rc8 17 Rac1 Re8 18 Nc5 Bf8 19 Bxe4 dxe4 20 Ne5 Bg7 21 Nc4 The knights are better than the bishops in this position as they, unlike Black’s minor pieces, reach annoyingly into the hostile camp from their advanced outposts. 21 … Rc7 22 Rb1 Bf8 23 Rfc1 Qg5 24 Kh1 Qh4 25 Qd2 Rcc8 26 Rb7 White takes the seventh rank as a reward for his patient manoeuvres on this wing. 26 … Rcd8 27 Qe1 Rd5 28 Rxa7 (see diagram 1) 28 … Qh6 Apparently changing his mind about restoring material parity, but if 28 … Bxc5 29 dxc5 Rxc5 30 Nd6 Rxc1 31 Qxc1 Rf8 32 Kg1 Qf6 33 Nxf5 gxf5 34 Rc7 Rd8 35 g3 White probably has a technical win. Gligoric elects to keep his bishops in an attempt to complicate matters. 29 Qg1 A remarkable defensive precaution I suspect only Petrosian could have conceived. If now 29 … Bxc5 30 dxc5 Rxc5 31 Nd6 Rxc1 32 Qxc1 Rf8 33 Qxc6. 29 … Bg4 30 Ra5 Be2 31 Nb3 Bb4 32 Ra4 Rb8 33 Ne5 Rbb5 34 Rxc6 White’s extra pawns prevent a breakthrough by the opposing rooks, so Black soon decides to sacrifice the exchange in the hope that the bishop pair will be able to save the day.