Only Part of the Analysis Tree Changes Each Move!

One thing that makes chess “easier” is that only two things have changed on the board since the previous time you had to decide on a move:

1. Your previous move
2. Your opponent’s previous move

That means IF you perfectly understood what was happening on the board last move (and that’s a big if!), then, unlike a problem in a book, you don’t have to start over from scratch to figure out what is happening this move – you only need take into account the consequences of the two moves that happened in-between.

The following is an easy example: Suppose your Rook on d1 was not in danger on the previous move, and no direct or indirect consequence of either new move affected d1, then the Rook must still not be in danger.

That is why we hear such guidelines as “Each time your opponent makes a move, ask yourself ‘Why did he make that move?’ and ‘What can he do now that he could not do before?’” You can even ask, “What are all the legal moves he can make now that he could not do before?”

The above guidelines often overlook the other consequence of the opponent’s move, which is “What was his piece doing before his move which it is not doing now?” This idea of checking to see what a piece is “no longer” doing is even more important when considering your move: “If I move this piece, then what was it doing before that it will no longer be doing now?” I have many students who often lose material because they are so interested in what a piece will be doing after their move that they forget that it was doing something important (like guarding material or preventing checkmate) on the square where it resided and will no longer be doing so.

Interestingly, the extra knowledge about only taking into account recent changes works better for stronger players! Why? Because stronger players have better board vision and more seasoned logic to account for the changes since the previous move. Weaker players, due to lack of board vision or even carelessness, often do not take into account all the aspects of a position and move hastily or with incomplete knowledge. The consequence for a player who moves without considering the necessary information is that IF, on the next move, they only take into account the changes in the position, then they also continue to miss the “carry-over” problems from the previous move! We will call these leftover problems because they were “left over” from the previous move!

For example, suppose a player does not notice a particular weakness which his (also weak) opponent does not exploit. Since his opponent’s move does not exploit the weakness but rather does something else, then if the player just says, “What can he do now?” based solely upon the opponent’s previous move, he will continue to overlook the weakness and will again allow it to be exploited on his opponent’s upcoming move. When this happens to both players, this often leads to the so-called “comedy of errors” where both continue to miss something that was originally missed several moves ago.

This leftover problem does not occur nearly as much with stronger players, not just because of their superior board vision, but also because their opposition is much stronger, and does not leave “unattended business” lying about the board. In other words, if a strong player overlooks something, then his opponent usually exploits this error, and the overlooked problem is resolved in the opponent’s favor. But with weaker players, once both players have missed an idea, that leftover problem may remain around several moves until either 1) one player “accidentally” notices it and either fixes it (if that player was the culprit) or takes advantage of it (if the noticing player is the opponent), or 2) one of the players unknowingly makes a move which changes the position so that the leftover problem disappears.

The result of that difference between strong players and weaker ones is that weaker players, even if they are taught to look only for the differences caused by the previous move, often adjust their thought process to include looking for leftover problems. While this widening of their thought process is understandable, it is terribly inefficient, since that means a weaker player sometimes approaches a position more like a problem, in that he has to solve everything all over again each move, and not just carry over the correct information and account for the differences. This is a terrible burden for the weaker player who, probably correctly, does not trust himself.

So what can be done by a weaker player who wants to play efficiently but is afraid of overlooking a “leftover” problem? There is no perfect answer, but here are some suggestions:

1. Look for leftover problems during your opponent’s move. But if you find one, don’t slap your head and yell out loud “Oh, what did I miss?!?!” That tends to tip your opponent off too, and he will use his move to identify and fix – or take advantage of – what you found. Of course, some players make exclamations like this purposely as a plot to lure their opponent into a trap. However, that ploy is also dumb because if your opponent is smart and you alert him – even as a ploy – he will be LESS likely to fall into the trap, since the main two possibilities are that you blundered or that you are trapping him, and he will make sure to figure out which one it is!
2. Work on improving your board vision so you miss less. This can be done by doing board vision puzzles or just playing lots of slow games.
3. Take your time and be careful on each move. If you are thorough, then you are likely missing less. That in turn means you can be more efficient next move and not have to worry about leftover problems nearly as much.
4. Practice an efficient and consistent thought process. If you have a good thought process (such as one that includes the question “If I make this move, what are all the checks, captures, and threats he can make in reply, and can I safely meet them all?”), then you will find most, if not all, of the key problems in the position.

There is one instance where a leftover threat is normal and must not be overlooked! This “normal leftover” occurs when you meet an opponent’s threat with a zwischenzug – an in-between move – or counterattack, and temporarily ignore the threat. In that case you purposely allow the original threat to still exist, so don’t forget about it next move or you could lose the game immediately!

Let’s summarize what should occur during analysis: A player creates a mental “analysis tree” of moves that are possible. Once a move is made, he can trim that tree to include only the moves that were actually made. If the opponent makes a move that was not on the tree, he should see how that move affects the position, and generate new branches. If his opponent’s move was on the tree, he should verify previous analysis of that move and add new analysis. In general, any new analysis is most efficient when it focuses on the changes in the position made by the previous move, including both the creation of new possibilities and the elimination of old ones.

So, from a practical standpoint, using the “What are ALL the reasons my opponent made that move?”,  “What are ALL the things he can do to me now and could not do before (and can no longer do)?”, and “What are his new threats, if any?” type of questions are all very helpful in a practical sense, and powerful shortcuts for thought efficiency. However, these shortcuts work much better once a player is strong enough that leftover problems are likely a non-issue. So play slow games and learn to be thorough and careful!