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Friday, October 21, 2011

Critical Points

According to GM Arthur Yusupov, “To many people it seems that grandmasters simply calculate variations a little deeper.  Or they know their opening theory slightly better,   But in fact the real difference is something else.  You can pick out two essential qualities in which those with higher titles are superior to others; the ability to sense the critical moment in a game, and a finer understanding of various positional problems.”

The ability to identify critical moments in a game is important because it is those positions that will influence the further course of the game.  In fact GM Edmar Mednis, writing his great book titled How to Beat Bobby Fischer in which he analyzed Fischer’s defeats, always showed the position where he isolated the losing move; the move where Fischer missed the critical point.  Also, sometimes in GM analysis you will read comments such as, “Not a bad move, but it embarks upon the wrong plan.” Or some similar comment. These are critical moments.
Every strong player has the intuition that tells him when he has arrived at a critical position, bu,t as with any GM’s intuition, it is often difficult to define exactly when such positions are reached.  I think sometimes GM’s cannot explain such things…they just know.

You would think working with an engine would make it easy for us to know when a critical position has arisen on the board, but that’s not the case because engines, critical position or not, treat every position the same and calculate variations.  GM Jonathan Rowson spent an entire chapter in his book, The Seven Deadly Chess Sins, discussing how to identify critical positions or key moments.  Rowson wrote, "To miss such moments can be considered ‘sinful’ in that it usually results from a basic misunderstanding of the nature of chess assessments and of how they can and do change.”  He then went on to explain, “…it is very difficult, if not impossible, to give any clear definition of what a key moment, or critical position actually is…”  Still, Rowson went on to try and define what the circumstances are and how, when we see them, to know we have reached such a position.  His list:

1-You begin to see pending counterplay for your opponent
2-The prevailing trend seems to have stopped and you can’t see any way for the advantage (for either side) to be increased
3-You have lots of reasonable moves, but none seems to be outstanding
4-You opponent’s last move was unexpected or in some way unusual

In OTB games these are indicators that a critical position has been reached and a careful positional reconnaissance needs to be performed and the position reevaluated.

In Modern Chess Analysis, CC GM Robin Smith gives the following signposts that warn you that you have reached a critical position in you analysis. When you see these signs being given by an engine, take heed:

1-The current evaluation is saying one thing but the trend, or an engine vs. engine tournament from that position, is indicating otherwise.
2-Different programs suggest different moves
3-Engines are suggesting a move in the type of position they often do not understand.  This usually involves castling, exchanging pieces in the ending when such exchanges are not forced, entering positions in which there are highly forcing lines and moves that alter the P-structure.
4-The potential exists for creating positions of a type engines do not understand like fortresses
5-In theoretical positions the engine’s evaluation differs from that of GM’s
6-One side seems to have an advantage but the engines can’t see a way to increase the advantage.

When you see any of the first four indicators in your OTB game, you must reevaluate the position. GM Alex Yermolinsky discusses this, what he calls “trends,” in his book, The Road to Chess Improvement. Of course this is going to call for some understanding of facets of the game too many lower rated players like to ignore: strategy and endings.  It's equally obvious that average players aren't going to excel at this kind of thing, but it does help to be aware of such things exist.

In conducting proper engine analysis, if you see any of the six signs coming from your engine, you know it’s time to evaluate things from a positional point of view.  After playing on Lechenicher SchachServer, where engine use is allowed, for the past several years I can tell you the above listed six signs happen frequently in almost every game. Of course none of us are Grandmasters, so all the advice in the world is not going to guarantee we will make the right decision, but I can tell you a few things that may help in making sure you select the best line.

As several titled CC players have noted, the analysis must be broad before you start going deep.  That means being interactive with your engine and looking at as many moves as seem reasonable to you and adding them to the suggested engine move list.  When you have narrowed things down to a few plausible moves, only then can you let the engine evaluate the different lines.  And bear in mind a short evaluation time won’t do; it may take several hours and some shootouts using a couple of different engines from the position of interest before you can get a reasonably accurate idea of what the best continuation is. Sometimes you will just have to use your judgment.  Take the following position:

In this position after 1…Bc8, but it should be clear that Black is going to have a very hard time getting his B and a1R into play and that can’t be good even though the evaluation shows White is only about ½ Pawn better.  The surprising thing is that if you back up a couple of moves from the diagrammed position, the engines don’t even recommend White’s playing for the P-push to c6 because they do not see the position as anything more that slightly in White’s favor.  Run a shootout from the position it soon becomes clear that Black is reduced to complete passivity and White quickly establishes a decisive superiority. 2…Be8 fared no better.  Black must search for a continuation earlier in the game that does not allow White to advance his P to c6 unless he is content to hope that his opponent relies solely on engine suggestions and avoids pushing the P to c6.  Of course if it turns out that White does some interactive analysis on his own and discovers the P-push, Black will be in serious trouble.  So even with engines it is possible to play what NM Dan Heisman calls “hope chess.”  You play a move and hope your opponent doesn’t find the best reply.  It also emphasizes the point that even engine analysis requires some human input and that can be a valuable learning experience even for us non-GM’s,

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