Editing Tigran Petrosian (section)

=== The positional exchange sacrifice ===
Petrosian was known for his use of the "[[The exchange (chess)#The exchange sacrifice|positional exchange sacrifice]]", where one side sacrifices a rook for the opponent's bishop or knight. Kasparov discussed Petrosian's use of this motif:
{{quote|Petrosian introduced the exchange sacrifice for the sake of 'quality of position', where [[Initiative (chess)|the time factor]], which is so important in the play of Alekhine and Tal, plays hardly any role. Even today, very few players can operate confidently at the board with such abstract concepts. Before Petrosian no one had studied this. By sacrificing the exchange 'just like that', for certain long term advantages, in positions with disrupted material balance, he discovered latent resources that few were capable of seeing and properly evaluating.{{sfn|Kasparov|2004|p=12}}}}

{{Chess diagram small
| tright
| Reshevsky vs. Petrosian, 1953
|  |  |  |rd|qd|  |kd|
|  |  |  |  |rd|pd|pd|pd
|  |  |nd|  |  |  |bd|
| pd|pd|  |  |pl|  |  |
|  |  |pd|pl|  |ql|bl|
| pl|  |pl|  |rl|  |  |
|  |bl|  |  |  |  |pl|pl
|  |  |  |  |rl|  |kl|
| Position after 25.Rfe1
|reverse=true
}}

One of Petrosian's most famous examples of the positional exchange sacrifice is from his game against [[Samuel Reshevsky]] in Zurich 1953<ref>{{Cite web|url=https://www.chessgames.com/perl/chessgame?gid=1106248|title=Samuel Reshevsky vs Tigran V Petrosian (1953)|website=chessgames.com}}</ref> ({{em|diagram}}). Reshevsky, as White, appears to have an advantage due to his strong {{chessgloss|pawn centre}}, which may become mobile after Bf3 and d4–d5. Petrosian realized he was in a difficult position because of the passive placement of his pieces, relegated to defensive roles. He further understood that White might also advance on the {{chessgloss|kingside}} with h2–h4–h5, provoking weaknesses that would make it more difficult to defend later on. Faced with these threats, Petrosian devised a plan to maneuver his knight to the square d5, where it would be prominently placed in the centre and blockade the advance of White's pawns.

:'''25... Re6{{chesspunc|!}}'''

With the rook vacated from e7, the black knight is free to move to d5, where it will be attacking the pawn on c3 and help support an eventual advance of his {{chessgloss|queenside}} pawn {{chessgloss|majority}} with ...b5–b4.

:'''26. a4 Ne7 27. Bxe6 fxe6 28. Qf1 Nd5 29. Rf3 Bd3 30. Rxd3 cxd3'''

The game was eventually drawn on move 41.{{sfn|Petrosian|1990|pp=68–69}}