| offramp: This was an extremely tense game. Game 12 of the best of 24 game match; played on 20th & 21st April 1963. Petrosian was leading the match at the time 6-5. In many of his previous white games Botvinnik had been offering a Queen's Gambit. Petrosian had been accepting that gambit and Botvinnik had really been getting nowhere. In this game, however, Petrosian plays one of his favourite moves in the QGD: 3...Bf8-e7. This gives Botvinnik the chance to unveil some powerful home preparation. Botvinnik plays 7.g2-g4!
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This is not a novelty; it had been played in Botvinnik vs Bronstein, 1952. Petrosian's defends in an analogous way to variations he knew from the Caro-Kann. After 12...Nf6-h5 we reach this position:
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This may seem like a far-out, non-standard position. In fact Botvinnik must have been totally incredulous: he had had a very similar position <30 years earlier> in Botvinnik vs Alatortsev, 1934. Here is the position after 17...Be6 in that game:
click for larger viewBut - amazingly - Petrosian plays the position far better than his experienced opponent. Salo Flohr criticizes 15.Bg6+ and 18.Nh4. Flohr also says that 21.Qg4+ is useless and that white should have castled. When black's knights return from their rims the visual difference in coordination between the two sides is noticeable. After 28...Nf6:
click for larger viewAfter white played 36.♖f8-f1,
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Salo Flohr says, <"...Many people did not believe it - 'someone is having us on!' But no, it was not a joke. In the hall, there were 1,500 witnesses - yes, this is what Botvinnik had played. Now of course, Petrosian will sacrifice the exchange on e5. Tal would do so like a shot, especially if in serious time trouble. But 'that is not how they play'!"> Flohr means 36...♖4xe5! 37.dxe5 and now I think 37...Ne4
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Black has a huge amount of play for the exchange (and a pawn). That ♘e4 is worth any rook. Petrosian, rightly or wrongly, or obliviously, played 36...Nc4 instead and the game soon petered out to a draw. | 
Kibitzing
