Grandmaster Lev Polugaevsky was a complicated chess player. Although – ironically – his name means “lion”, it has been said that he was a very timid kind of guy, and that this was the reason he was never able to directly compete for the world championship. He is famous for taking opening preparation to an unprecedented level, and it has even been suggested that his huge emphasis on pre-game analysis was the result of a lack of confidence in being able to solve the problems over the board, despite his undoubted practical strength.

At the same time, he played the sharpest, most complicated games, in which often his king barely survived before his counterattack began. He carried out the riskiest ideas – always, though, they were backed up by deep analysis, either before the game or during it. In many games – such as the one we will be seeing today – his king lingered in the center while a counterattack was prepared.

His raison d’être was a very sharp variation of the Najdorf which is now known as the “Polugaevsky variation". In this variation Black walks a thin line, subjecting his king to a number of possible sacrificial blows. All of this for a potential positional advantage, or – if White declines to take up the challenge – a “half-tempo” lead compared to the main lines. Polugaevsky invented the variation and analyzed it in incredible depth. Such devoted work on one specific variation of the game of chess might seem strange or limiting to some people, but think of the millions who spend their lives in an office, processing forms all day.

At this point Gruenfeld was quite simply intimidated by the surprise blow 20...Nb3+ and played the losing move 21.Kb1?, after which Black remains with an extra piece. There is still some excitement to come, but unfortunately it meant that Polugaevsky did not get to reveal the deep calculations he made when he decided on 17...b4. We will now look at this fantastic variation which could - should - have happened in the game, but did not:

According to Polugaevsky's annotations, he calculated the majority of this during the game, taking about an hour to decide on 17...b4. While it is the norm rather than the exception for strong players to claim that they calculated more than they actually did, Polugaevsky does not seem to be the kind of person to do that. I do not know how much Gruenfeld saw. Although it appears that 21.axb3 should lead to a draw while the move in the game (21.Kb1) is obviously much worse for White, it is very easy for a player to be unsettled and confused by the situation created by his opponent. Perhaps he saw the forced variation with the king walking up to f4, with many pieces hanging, and thought, "there must be a win for Black." Such a vague assessment, based on emotion, can easily cause desperation to set in, so he played the losing move.

So, Polugaevsky's enormous calculations at move 17 were wasted - or were they? The variations at move 21 did not come about, but their existence baffled Gruenfeld to such an extent that he made a losing move instead.

We all know that what seems obvious in post-game analysis - that by method of elimination White had to choose 21.axb3, regardless of the dangers - can seem completely confusing with the clock ticking. Fears, worries and self-reproach can all get in the way of rational thinking and literally freeze the mind. On the other hand, sometimes competitive situations can bring out a player's creativity and allow him to find ideas that he might miss when analysing in the comfort of his home. The big difference here is that the complications were initiated by Polugaevsky. Thus the situation was upsetting and confusing for Gruenfeld, regardless of the objective evaluation - the more so since his choice of 6.Bg5 indicated that he wanted to be the one doing the attacking!