The candidates tournament of 1953 in Zurich to choose a challenger against Botvinnik was brilliantly annotated in a bookshelf-busting 350 page book by David Bronstein. He was one of the participants in the 30-round (!) double round robin of 15 of the top players in the world at that time, including former world champion Euwe and future world champions Petrosian and Smyslov, along with three of the greatest also-rans of all time: Bronstein, Keres and Reshevsky.
The genius of the writing in Bronstein's 1st (and only?) chess book is that the key plans for each side are detailed in a verbal style that can be understood without having a board in front of you, i.e. pointing out that the key to the position is a certain weak square, and that the next 10 otherwise incomprehensible maneuvers are each side's effort to control it. Many GM's have called it their favorite book of all time.
Best of all, it's still in print and costs $10.17 at Amazon (I got it for $9 at a sale at the USATE last year), so no excuses, you should really own this.
Not convinced yet? Over the next several weeks I'll post my top 20 favorite moments from the tournament (if 20 seems like a lot there were 210 games so I was actually trying to be very selective). Starting with....
It's Black to move in this Nimzo-Indian middlegame, and it looks to me like Black has reason to panic - White has a simple plan of organizing a center pawn push which will activate his bishops and enhance his kingside threats. Petrosian prepares to counter by organizing his heavy pieces in the middle....
21. ..... Re7
22. Bg4 Qe8
23. e5 a5
24. Re3 Rd8
With the growing threat of e6 to follow, forcing ...f6 as the first of possibly many future defensive concessions. But looking back over the last few moves it's easy to see in retrospect Black was planning...
25. .... Re6!
Bronstein: Black must stop White's pawns, so Petrosian gives up the exchange at a spot of his own choosing, freeing e7 for the transfer of his knight to d5 [Centralization! Blockade! -IM]. Of course, Black gets good compensation for the exchange: his knight is much stronger on d5, as is his bishop, which no longer has an opponent.
Kasparov: ...let us ponder over the position and ask ourselves: why, in fact, should a rook be stronger than a minor piece here? After all, a rook requires open lines, it needs something to attack, whereas minor pieces require strong points and pawn support. In the given instance there is a shortage of open line, and it is no longer possible to stop the knight from reaching d5, where it will be impregnable. In addition, from d5 the knight will be attacking the c3 pawn, and if the white bishop does not manage to switch to d2, it will remain 'vegetating' at b2. It is practically impossible to break Black's light-square defences: White simply does not have resources to do so.
Amazing! Yet so simple when explained....except that this exchange sacrifice
is complicated by the fact that the position is not fully closed (compare this with game #2 below) - there is potential for an opening in the queenside, and this is what Reshevsky first tries for and what Petrosian had to anticipate - if the queenside is opened it is likely that White may still be able to win.
26. a4 (the rook is not running away after all) Ne7! (not being baited into ...b5 when 27. d5! follows opening the game)
27. Bxe6 fxe6
28. Qf1 Nd5 (completing the plan)
29. Rf3 Bd3
And here, Reshevsky returned the exchange with Rxd3, after which the game was soon drawn. An exciting game, and a defensive triumph.
In the next round, Reshevsky had the Black side of the Nimzo-Indian. Was he inspired by the game above? You be the judge...
Bronstein: How is Black to meet the impending attack on his king? He must ready himself to weather the storm by placing his pawns on the dark squares, his rooks on the e-file and his knight at d6 where it blockades the pawn and covers the light squares.
And so he does...but to do this requires forseeing an exchange sacrifice.
21. .... Re7
22. Bd2 Nb7
23. f4 Rfe8
24. Bc3 f6
Bronstein: Black shores up e5 with might and main, pressing simultaneously on e4 with the hopes of inducing f4-f5.
What is this?? Averbakh consents to closing the position, which appears to ease Black's defense (the game was drawn in a further 8 moves). After all (as Bronstein points out) 25. fxe5 fxe5 26. Rf1 followed by doubling of the rooks on the f-file gives White the advantage, since a Black rook will be tied to the weak e5-pawn. The key lies in the improvement for Black - 25. fxe5 Rxe5!, when after Bxe5 Qxe5 "the black knight which would enter d6 would be not a bit weaker than a white rook." (Bronstein)
Another exchange sacrifice! One that didn't appear on the board and yet one that determined the course of the game. All the same, this sacrifice, if it occurred, is a simpler case than the Petrosian example because here there is little prospect of open play anywhere on the board after the sacrifice.
I wish I had saved the position, but a week after reading this I pulled off this exact sacrifice (rook on e5 for the dark-squared bishop) against a computer in the Nimzo-Indian, and the surprised machine shuffled its pieces for the next 50 moves until it called a draw. A good trick to know.