Exeter Chess Club: How do Chess-Players Think?

These are extracts from Simon Webb's superb series of articles for Barry Wood's old CHESS magazine. Simon showed a panel of players a position and recorded their spoken thoughts for ten minutes. The articles are well worth digging out: obviously there is much more in the articles than I can present here, but it will give you a flavour of the sorts of issues that can arise. The joy of this technique, of course, is that you can repeat the exercise with the same or different positions in your own club.

The positions are presented twice, one without commentary if you would like to attempt 10 minutes thought on them, and once with a comment cherry-picked from Simon's much more detailed discussion.

I have also added two famous examples of master's thinking.

1 - W to move: assume in haste, repent at leisure!
2 - B to move: analyse your way to success
2/78 - B to move: what is the point at issue?
6/78 - W to move: candidate moves?
7/78 - W to move: begin at the end
10/78 - W to move: playing by analogy
deG - W to move: what makes a difference?
LCM - W to move: masters at fault?

1 - W to move: assume in haste, repent at leisure!

Comment on #1

2 - B to move: analyse your way to success

Comment on #2

2/78 - B to move: what is the point at issue?

Comment on #2/78

6/78 - W to move: candidate moves?

Comment on #6/78

7/78 - W to move: begin at the end

Comment on #7/78

10/78 - W to move: playing by analogy

Comment on #10/78

deG - W to move: what makes a difference?

Comment on (de Groot)

LCM - W to move: masters at fault?

Comment on Lasker-Capablanca

1 White to play: assume in haste, repent at leisure!

"...Thus all the panellists seemed to make a judgement about the position instantaneously, and spent the rest of the time trying to find evidence to support this judgement, Clearly it is very difficult to approach chess in a truly objective manner -- so much seems to be based on 'instinct'." -- Webb

[Comment from DR: I might add, that a misjudgement of this sort might lead to much fruitless searching for a winning line if you think you are better. Blumenfeld used to advise trying to look again with a fresh eye at a position to see if you haven't overlooked some simple tactical point, but no less important to make sure you don't overlook some important positional point. I have known players ignore really key features of a position (a Pawn majority, and open file) because they thought they knew what the position was 'about'. Positions in books are selexcted to be 'about' one clear theme. Positions in most games are usually more complex!]

2 Black to play: analyse your way to success

"A striking example of the different depths to which the players analysed was provided by the move 1...P-QB4. GJ[112] considered this for about five minutes, but in general terms, without actually mentioning a reply for White. JW[155] and IC[149] got as far as 1...P-QB4 2. Q-B2 R-R7 3. QxBP Q-KB3 4. Q-KB5 before giving the line up, but RW[208] continued with 4...Q-N7 5. R-Q8 R-R8 6. Q-B8 Q-N8 7. RxNch K-R2 8. Q-KB5ch and mates. I had always thought that strong players don't analyse much deeper than weaker players, but this is a clear example to the contrary." -- Webb

[Comment from DR: This belief is rather widespread. de Groot's research certainly seemed to argue more for the importance of judgement than calculation, but there has been a lot of work since which shows the importance of seeing ahead.]

2/78 Black to play: what is the point at issue?

"They all settled fairly quickly on a king move so as to be able to get the rook into play with ...R-QB1 (...) The main problem in this position is whether to play ...K-R1 or ...K-R2. (...) Although having ten minutes to use up, two of the panel (of four -- DR) gave scarcely any consideration to which was the better king move." -- Webb [Comment from DR: de Groot's research is also relevant here. What his tests seemed to show was not that masters analysed very much deeper, but they homed in on the critical lines and issues much more quickly than non-masters. ]

6/78 White to play: candidate moves?

"Korchnoy played 12. N-KN5! (-K4-B5), a move not considered by any of the panel...

"JN[236] thought almost exclusively in terms of concrete variations, whereas GJ[112] went to the opposite extreme... RW[208] and SJ[165] also gave very few concrete variations, and this may be more a question of style than strength...

"IC[149]... seemed to have the best-organised thought processes (...) It is not clear, however, whether this logical approach is necessarily all that effective, for it could be argued that if IC had adopted the RW approach of looking at moves twice he might have spotted 1. P-K4 B-N5 2. P-Q5 N-Q5! which seems good for Black" -- Webb

[Comment from DR: This position illustrates for me quite nicely Kotov's notion of 'candidate moves': Korchnoi's actual choice wasn't even considered by the panellists. Korchnoi may even have reviewed, and rejected, other moves that were not considered by them.

Kotov expands his approach to analysis by saying once the list of candidate moves is drawn up, each branch should be considered once and once only. IC has clearly read and believed, and this player may be more efficient because of it, but at least while we are improving this may be at the cost of accuracy. de Groot used to describe an approach of 'progressive deepening', and this may not just a more common approach but a more appropriate one for positions which are not highly tactical.]

7/78 White to play: begin at the end

"JN[236] and RW[208] had far more idea what they ought to be doing than the others, and this supports the widely held supposition that the greatest difference between stronger and weaker players is in the endgame." -- Webb

[Comment from DR: Howard Staunton complained that only the 'magnates' of the game were really skilled at endgame play, and this remains true!

But Capa advised, that chess study really should begin with the endgame.]

10/78: playing by analogy

"...Although experience is an advantage in telling a player what to look for, it can also restrict you into considering only 'normal' moves.

"JM [237] 's idea of meeting 1. P-B5 with ...PxP and ...P-K5 (was) difficult to spot, because ...PxP is an abnormal way of meeting the thrust P-B5. This also applied to RY[160] and RN [165], who didn't consider ...PxP because it would have looked anti-positional to them. To AP [ungraded player], however, ...PxP was the obvious reply...

[Comment from DR: I like this observation. It may be that stronger players actually consider more 'stupid' moves than wekaer ones - dismissing most of them, but not ruling them out without a glance! It may be that this is the only possible explanation for, say, some of Tal's moves...]

White (de Groot ) to play: what makes a difference?

Chess master and psychologist de Groot gave this position to Alekhine, Keres, Euwe and other GMs at the 1938 AVRO tournament, as well as to a number of weaker, but still expert, players.

All the GMs except Flohr quickly found the win with 1. Bxd5 (1...exd5 2. Qf3 Qd8 3. Rfe1 Kg7 4. Ng4 Nxg4 5. Bxe7). They also analysed other forcing continuations like 1. Nxc6, which Alekhine considered just as strong and which Flohr actually preferred.

Hardly any of the other players suspected there was a forcing solution (even after 15-20 minutes, much longer than the GMs. For the most part, they opted for safe positional moves like 1. Rfe1 or 1. Bh6; nothing alerted their antennae to a concrete solution.

Every solver thought: White has an isolated d-pawn, so endgame problems, so attack now. But only the GMs chased it down to a line 4/5 moves deep. The lesser masters seemed unable to overcome two barriers to seeing the tactic: the safe appearance of the Black position, and the anti-positional appearance of 1.Bxd5.

"It is by no means easy to detect these chance factors which are not based on obvious strategic factors", conclude Pfleger and Treppner, rather gloomily.

Oh, Flohr's idea? Looking for something even better than Bxd5, he hatched 1.Nxc6 bxc6 2.Bxd5 cxd5 3.Bxf6 Bxf6 4.Nd7, winning the exchange... but it is only the ghost of the knight that goes to e7!

Lasker-Capablanca #10 1921; White to play: masters at fault?

This is a similar case, where the GMs may have got it wrong: Breyer analysed a win starting 15.Bxf6!

It looks anti-positional to gove up the Bishop, but Breyer claims an advantage in all lines:

17...Bxf6 18. Bxd5 exd5 19. Ng4 Bg5! (19...Bd8 20. Qf5) 20. f4 exf4 21. Qf5 Bc7 (else 22. Qxd5 a6 23. a4) 22. Nxd5 Kh8 23. Nxh6 gxh6 24. Nf6 Kg7 25. Nh5+ with mate in two.

I have seen this analysis "busted", and I don't feel qualified to judge: but if Lasker didn't overlook something important, then Breyer did!

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This document (webb2.html) was last modified on 30 Jul 96 by [cool blue cat]

Dr. Dave