The pawn sac was perfectly sound, although 18.Nxe4 would probably have kept White in the game. And I don't think Botvinnik was the kind of player who would have gone astray in the complications; in any case, such a thing would be more likely to happen to White. I like this game because I see it as a profound demonstration of the dynamic possibilities inherent in the Sicilian Defence. I found Botvinnik's piece play especially attractive, but the standout moment was the pawn sacrifice, which I believe was as good as any double piece sacrifice.

Nunn writes: "It is always nice to be able to play a move like this - there are four pieces trying to stop this advance, yet Black can play it. Moreover, the move creates such serious threats that Black need not move his attacked bishop for now. Grandmaster Jonathan Mestel once expressed a general principle: the more pieces there are trying to stop a pawn break, the more effective it will be if carried out successfully. Here we have a case in point.

<Any decision based on judgement is a gamble.>

Are you quite sure? Judgement is a part of the thought process that leads us to our decisions - if it is conclusive then there should be no risk involved. Of course, there is an element of risk involved in any decision we take, but that is like calling chess a game of chance. If there is a clear intent, and a confidence that the outcome will be as predicted, then I wouldn't call the decision a gamble.

It also depends on what you mean by judgement. If you mean the act of judging, which is to say forming an opinion after thinking about the situation, then even a one move checkmate, which clearly does not involve risk, is based on judgement. But even if you mean the situation in chess where a player decides that a certain set of advantages will outweigh those of his opponent, then any chess move where the outcome is not completely certain is a gamble. If all decisions in chess, as life, could be made with complete certainty, then we would say that chess has been solved, and it would not be worth playing at all. Far more important, I think, is the nature of this judgement, what it is based on. I don't think that an informed decision is a gamble, because rather than allowing chance to take its course, you are trying to impose some sort of control over future events. So whether or not a decision is a gamble really depends on the amount of information involved. If the decision maker believes he has enough information and is justified in his choice, rather than simply hoping that things will turn out as expected, then he is not gambling beyond the extent that any decision is gamble.

The Black Queen transfers to the King side from the square a5 by the route Qa5-a6-f6-h4