Friday, August 24, 2007

The PGA and PGU of chess tactics

Finally. Back in March I wrote about the CCT-rule. It was my intention to continue writing on that, and I did write a draft but it's not until now that I finished it. It could be a good idea to start reading that post, but I will try to make this one self-contained (which means some repetition). Also, the delay means I can write this one using the terminology of PGA and PGU, and using a diagram position that wasn't available at the time.

I still think that the CCT-rule (checks, captures, threats) is the by far best method to find tactics, especially simple tactics (which is especially important in blitzes, but obviously everywhere.) And it is a pure PGA, as against a PGU. (Learn about PGA and PGU here. Here's the very short version: PGA stands for principles of action, and PGA is principles of understanding.)

There are many PGU's in chess, including categorising different "motifs" like forks and skewers. But I've found it to be useless to actually systematically try to go through these in a game. It's a very useful skill to see these motifs quickly, and these terms are very useful in some ways, but non-useful to consciously go through one by one in a game. It's just too much, and too incomplete. The CCT-rule on the other hand is complete. It does cover all tactics (which doesn't mean that it guarantees you will find any tactics, of course, just that there is no tactic that doesn't begin with any of those.)

Checks, captures and threats and mentioned from time to time in many places, but it's mentioned together with lots of other stuff, some of it rather unimportant. (That's how I found it, literally as one of 100 or so ideas throws together on a web page). That indicates that its proper role and value isn't completely discovered.

I've found that there are several benefits to this scheme.

1. Covers all tactics (as mentioned above), which gives a feeling of "completeness", and sense of control (based on a genuine increase in control, so it's not an illusion.)

2. It gives a sharp line between categories of moves, making it simpler to mentally keep track of what you are doing. If you try out moves randomly, or based on some feeling about "importance", you basically have to keep track of the moves one by one, which often, for me at least, leads to chaos. I miss checking some moves, I double-check others, I jump back and forth between moves in a wildly irrational way. With the CCT-rule and that sharp line I get some sense oif what I've tried. (I still jump back and forth some, but not as much. There is a noticeable increase in control)

3. I often find tactics hidden behind a non-intuitive move that I otherwise may not have found. For example, you will easily find all queen sacs if they are not too deep. The problem with much tactics is that you don't even consider some moves (such as a queen sac, unless obvious), but with the CCT you do. There is no guarantee you will see the tactic just because you examine the first move, but you increase your chances anyway.

4. If you apply the CCT-rule consistently when doing tactics, the mind eventually starts to look for those moves automatically (as against in the beginning when you constantly have to remind yourself to go for these first, which feels kind of unnatural if you're used to the chaos-method of checking moves randomly based on 'feeling'). In other words, you look at the position and without any effort at all pick out the most crucial moves. That's a great thing. (No I'm not there myself completely, for the simple reason that I don't practice much, but I've seen some movement in that direction.) Doing the CCT will eventually become with feels right and natural.

For example: Take a look at the position below, it's from this post by BDK. He says: "One problem with trying to classify everything is that I become somewhat blind to tactics that don't fit into my schema.For example, here is a problem that I ran into today at CTB, with white to move." (Referring to the diagram below.)

That's one problem with using a schema of motifs. However, using the CCT-rule, the correct move, Bg8+ is literally among the first two moves to look at (which in fact is what I did look at immediately when I saw that diagram, and I solved it within a second, and that's not because I'm a great player, which I'm not), since it is one of two checks (and checks come first.) And once you examine that move, the rest comes naturally. Here's the diagram:

There are some difficulties (areas that need further development) with CCT.

Firstly, the T part. Because it isn't obvious what is a threat on the board, as against captures and checks. I've done some thinking and experimenting, and it seems useful to have the following two subcategories to find threats:

1. Look for unguarded pieces and see what moves you can make to attack that piece (often making a double-threat). (Unguarded pieces is something most player know to look for, but it's treated more or less as a random idea, just as the CCT-rule itself. Here, however, it's sorted under the T-part in CCT. It's part of a systematic, and realistic, approach.)

2. Look for moves where pieces of lesser value attack more valuable pieces (such as attacking a trapped piece by doing a pawn move).

Secondly, what to do after the first move. I admit that I mostly only apply the CCT-rule when doing the first move. However, it makes sense to apply it (in some way) further within the search trees as well, at least the second move. But it's tricky and maybe some simplified version is needed. I don't know, my plan is to automatize the CCT-rule as the root to begin with, and then worry about the rest. But eventually that question will become relevant, I think.


Blue Devil Knight said...

Good stuff!

Glenn Wilson said...

I like the distinction between PGA and PGU.

In this position after not seeing any mate-in-ones I immediately turn my attention to the Pawn on the seventh. Is there any way to Queen it?

That leads me to the answer I seek based on a goal of Queening the Pawn. I think a Threat (in the CCT) should probably include pawn promotion....

XY said...

I've considered that, and what makes me hesitant to include it is that it's only relevant for a small period in most games (if at all). And the CCT should be used every move.

Though of course, pawn promotion is a threat, so it does belong in the T category, I'm just not sure it deserves to be mentioned specifically. The jury is still out on that one.

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