Sunday, February 25, 2007

Piece activity (suggestions wanted)

The following is the section on piece activity from my 'chess thought process' manuscript (a drastic revision of the previous version). I'm including it hoping to get constructive criticisms (suggestions for additional subfactors, disagreements with the descriptions I've included, anything).

PIECE ACTIVITY
Piece activity is the most important strategic factor. There are three main dimensions of piece activity: mobility, freedom, and coordination.

A piece's mobility is the number of squares to which it can move. This is a simple subfactor to calculate: simply add up the number of such squares (e.g., a bishop cramped in on all four sides has mobility of zero). Also, note that all mobility is not created equal. The most valuable real estate is on your opponent's side of the board, where you will be able to generate the most threats. This is why it is so useful to have pieces (especially knights) in the center of the board.

Mobility is inextricably tied to pawn structure: the pawns determine which bishops are good and bad, which files are good for the rooks, where the outposts are for knights, etc.. Often a simple pawn move will free a piece from its prison or give a knight a sweet outpost in the center of the board.

The second activity subfactor, freedom, which is the number of squares to which a piece can move while still carrying out essential defensive roles. Even if a piece technically has high mobility, it could be tied down to playing a passive defensive role. A pin against the king leaves the pinned piece with no freedom to move from the line of the pin.

The third subfactor, piece coordination, is the most subtle dimension of piece activity. Pieces are coordinated when they toward a common goal. For example, one piece may attack an escape square of the opponent's king while another piece is poised to put the king in check. If your pieces have high freedom and mobility, but are not working in concert for an attack, then consider how you can increase their coordination. Goal examples: coordinate an attack against the f7 square to weaken the opponent's king, hammer at the c-file by forming a rook battery.

When evaluating a piece's activity it is often helpful to consider where it 'wants' to be on the board (e.g., a Rook wants to be on an open file). Often it would only take a move or two to get a piece to its most natural square, and often the trajectory involves making threats along the way. If there is a piece that is especially low in activity, increasing its activity should become a priority. You don't want it pathetically watching from the sidelines when an attack starts.

6 Comments:

Blogger Temposchlucker said...

Other factors that play a role in piece activity:

The security of the home square. Think of outposts where knights can be driven back by pawns.

A pathway into the enemy camp is double edged. Your enemy can use the same path to reach you. Can you be challenged along an open line?

The quality of the covered fields. If you managed to bring a knight to b6 into the enemy camp it can be utterly useless because the enemy already abandoned that part of the board. There must be targets in the neighbourhood.

Can you use the pathway to move to a better home, closer to the enemy targets? Think of placing a rook at the 7th rank.

2/26/2007 04:47:00 AM  
Blogger Blue Devil Knight said...

Tempo: security of a home square is interesting (the others are all good, and would fit in well as examples of the claim that 'not all mobility is created equal').

My first reaction is that security is useful, but falls under threats rather than activity (though it may be a good example to show how different evaluation factors are not independent). Material (including threats against material) is the first, and most important, evaluation factor.

I wonder if I should include a discussion of space in this section. I've put it in my section on pawn structure....I will think about space some more...

2/26/2007 11:46:00 AM  
Blogger Jojosh_the_Pi said...

Perhaps a mention of the value of piece activity vs material? There can't a hard and fast rule about it, but it seems being down a Pawn or two with an active position is often better than equal material in a passive position. I've seen too many games where a position would be equal material, but it would not be very compelling to watch since one player had such a vise grip on his opponent.

In fact, there was a book (one of Silman's?) that specifically advocated jettisoning a Pawn in Rook and Pawn endgames if it would make Rooks active.

2/26/2007 10:33:00 PM  
Blogger Patrick said...

Academically the classification you give seems very "correct", but i think it would be difficult to employ this knowledge in a game.

To be more constructive, another factor is the importance of the piece's function. Maybe that doesn't belong in this section. For example, if you are going for an allout mating attack, you first sac the pieces that can least contribute in the attack. Why? Because their function is less important. Maybe they can sack for an important defender or to open lines somehow. Probably this doesn't belong under "Activity", depending on how you organize the rest of the document. Nice pics again.

2/27/2007 12:49:00 AM  
Blogger Blue Devil Knight said...

Jojosh: I should mention something about activity vs material, to link it up with the section on material, and mention like you said that many times it is a good idea to trade material for activity.

Patrick: I'm glad I haven't missed anything major (breaking activity up into mobility, freedom, and coordination is turning out to be very useful so far. It is like a light has turned on in my head and I am able to understand and explain things that were mysterious before).

Your guideline for making a mating attack starting with the least important piece is very cool. That could be part of the piece coordination (in combination with material) section (obviously, not everything fits neatly into the material, activity, king safety, pawn structure evaluation categories).

Also, I realized one reason 'space' (advancement of pawns) is so important is because it takes away some of what I am calling freedom of movement (in the next draft, just 'freedom') of the opponent's pieces. Especially for passed pawns, the opponent typically has to take away freedom from his pieces to block promotion. It isn't only mobility of one's own pieces that is improved by 'space', but the freedom of the opponent's pieces is hindered. (Add caveats about how increased space often means defensive resources of your own stretched too thin, and you are giving the opponent targets if your pawns advance too quickly).

I'm starting to think Heisman was not crazy when he called space a pseudo-factor. He just wasn't explicit enough to be useful to me at the time.

2/27/2007 08:44:00 AM  
Blogger takchess said...

http://www.chesscafe.com/heisman/heisman.htm
this may speak to last posts topic

2/27/2007 12:04:00 PM  

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