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The difficulties implied by the calculating process can be of different nature. There is certain fascination provoked by long combinations but if there are no major alternatives to the main line a strong player should have no problems calculating ten or more moves ahead. Things are of course by far more difficult if the opponent has choices, be it in the beginning, at a later stage, or all over the combination, even if the main thematic line lasts for only, say, four moves. Or else, the calculation may prove uneasy if the main line implies quiet moves (without check or piece capture).
Depending on the complexity degree of the calculating tree, the intuition should also be involved. There are positions where analyzing everything is possible only in correspondence chess or during the home preparation. It is always useful to have some safety nets on the way, such as the possibility of delivering a perpetual check or retrieving the sacrificed material with approximate equality. This would make one more confident when starting the combination, as an initial miscalculation would remain unpunished if noticed while the game advances.
In this section, I provide 4 extensively annotated games which illustrate the typical methods of calculating long variations.
Typical Psychological Mistakes
There are two typical psychological mistakes when calculating a long branchless line:
1) you know it could be good but do not have the courage to go for it and then you start looking for the opponent's defenses too obstinately. This could result in seeing ghosts and convince yourself that "it does not work".
2) you lose objectivity and wish from all your heart that the line worked for you, failing to notice the opponent's defensive resources.
As we see, these are two opposite cases and there is no simple advice to avoid them. "Believe in yourself" would help to stay away from situation number one, but it faces you with the risk of falling into the second category, one while "Be circumspect, double and triple check" might achieve exactly the opposite.
The natural advice would be to keep a balance between looking for your and your opponent's resources, but this is only part of it. Once again, I would mention understanding and intuition. These refer to the evaluation of the starting position and the question whether everything is ripe for concrete, forcing action. Not least, safety nets should help one to embark the long lines. The worst that could happen in this case would be spoiling an advantage, but not losing.
In order to illustrate the psychological aspects of the calculation, I provide 3 classical games and 1 instructive study by Kasparian.
Ever since Kotov, much has been written about candidate moves. But I have always had the vague feeling that this is an attempt to make our game look scientific to an even higher degree than it is and that most of the players do not really think or calculate according to this pattern.
At least to me, the candidate moves theory means something a bit different. This is by far not the first time that I invoke the notion of "intuition". A strong player should feel what he should do in the critical positions and calculate just to check whether his idea is right. Here are a few typical situations.
1) The term "candidates" surely applies when it comes to the optimal move order of a certain forced variation or combination.
2) I must, however, admit that there are certain situations when intuition is not entirely reliable and one needs to check things concretely after the few moves available, when the method of elimination may save one from trouble.
3) There are also situations when one has to choose between a couple of what may seem equally good (or bad) continuations. In this case, it is essential to evaluate the resulting positions correctly, both objectively and from a practical point of view. The latter refers to turn play one-sided if he is better or, on the contrary, to keep chances for counterplay if the opposite applies.
All the abovementioned cases are illustrated in 3 examples (2 games and 1 study).
This is a very delicate subject. One may play a very good game, systematically outplaying his opponent by peaceful strategic means, but against a roughly equally strong opponent, it is rarely possible to win by this method alone.
There comes a moment when one feels that concrete, unusual action is required, but then you need to effectively "see" the starting move of the winning line, or even the whole idea. But switching from the "quiet" mode to the concrete one is not always easy psychologically. Sometimes the task is complicated by the opponent's confidence or even his bluffing. It can also happen in a different way. After defending an unpleasant position for a long time, one gets so used with this situation that could have problems spotting his opponent's blunders.
I should make an important remark. The terms of "vision" and blindness" refer to tactical ideas which are not known from the usual books with positions for solving. If a player does not find a combination based on a well-known theme it means that either his chess culture is not well developed enough or he simply forgot it due to tiredness and pressure. I know the feeling very well, it is something like a nightmare. "What if I will simply not see the winning idea?"
This subject is also illustrated in 4 highly instructive examples.
In this section, you will find 30 interactive test positions which are organized in 5 subsections - Long Variations, Candidate Moves, Unjustified Optimism, Missed Opportunities, Vision and Intuition, and Move Order and Commitment.
Below I provide you with 5 interactive tests concerning the calculation of long variations.