Simple Chess by Michael Stean

Simple Chess by Michael Stean

Simple Chess by Michael Stean

---------------------------------------------------------------------------------

How do you go about forming long range plans when playing a game of chess? GM Micheal Stean presents his ideas and attempts to wisely keep them as simple as possible.  I would recommend this book to anyone who wants to understand the absolutely most essential basics of positional chess (from the point of view of an intermediate level player) without getting too complicated. In my opinion, this book could serve as a starting point for a requirements document for those who wish to build a computer program that attempts to play a positional game of chess.

Alternatively, one could use this book to predict the effectiveness of any proposed approach to playing a positional game of chess.

p.1-2" When faced with any problem too large to cope with as a single entity, common sense tells us to break it down into smaller fragments of manageable proportions. Simple Chess... tries to reduce the problem still further by recommending various positional goals which you can work towards, other things (i.e., material, development, security of king position) being equal... Simple Chess will provide... some elementary objectives which if attained should eventually decide the game... Essentially, Simple Chess aims to give you some of the basic ideas for forming a long-term campaign."

Stean speaks of the the activity of the pieces as being the 'most important single feature of a chess position'. This comment should not be taken lightly by those wishing to build a computer program to play chess. Note that when he says 'activity of the pieces' he seems to mean something different than 1-move 'mobility' - he seems to be sliding pieces around until they bump into a pawn (or land on an unsafe square) and are therefore 'constrained' in their activity.  Of course, piece activity is meaningless unless it is directed towards an objective - such as attacking an enemy piece or supporting a friendly piece. Piece activity can be used to constrain the movement of the enemies pieces.

Stean sees the pawn structure as the major constraint to the activity of the pieces. We can already see that an implementation of a chess program that looks at the activity of the chess pieces, as well as the constraints placed on piece movement by the pawn structure (and other pieces), as a direct reflection of Stean's ideas.

p.7-8“The most important single feature of a chess position is the activity of the pieces. This is absolutely fundamental in all phases of the game (opening, middlegame and especially endgame)... The primary constraint on a piece's activity is the Pawn structure...The job of the chess player must therefore be to use his skill to create a Pawn set-up which will allow his own pieces the optimum freedom and stability, while denying his opponent's similar scope.”

Holes in the attacking power of the pawn structure, which only can be determined by examining future pawn mobility, allow the identification of squares which can be used as outposts.

p.17"In general a successful attack can only be launched from a position of strength in the center of the board. This 'position of strength' can take various forms, the simplest being an outpost."

As the name suggests, an outpost is a square at the forefront of your position which you can readily support and from where you can control or contest squares in the heart of the enemy camp. To be useful, an outpost must be firmly under control and so should ideally be protected by a Pawn. Conversely your opponent should not be given the opportunity to deny you access to your outpost, so in particular it must be immune to attack by enemy pawns. This last condition is far and away the most important and can indeed be taken as the defining property of an outpost."

Outposts near the enemy's king are especially valuable.

p.24"an outpost in the vicinity of the enemy King is an excellent platform from which an offensive can be launched."

Pieces must be able to move freely within the structure of pawns. Moving freely should not mean that we consider only possible moves for the piece at its next turn. We should consider visualizing what each piece can do a few moves into the future.

p.38"The lesson to be learned here is that structure alone is not quite everything. The pieces must be able to coordinate with the pawn structure. After all, what use is a body without a soul?"

Pawns become weak by being unsupportable by neighboring pawns, and by being attackable by the enemy. Potentially weak pawns that are not attackable by the enemy require no defensive support from friendly pieces. Giving points in our evaluation function for doubled or isolated pawns without considering how attackable they are can cause incorrect (1) focus in our search and (2) evaluation of winning chances.

p.39,42"If the defending forces can be reduced to the menial task of protecting Pawns, they will not be able to offer much opposition to a full-scale offensive."

So what exactly is a weak Pawn and how is it recognizable? The answer is both simple and logical. A weak Pawn is one which cannot be protected by another Pawn and so requires support from its own pieces. Note that the criterion is the ability to be protected by another Pawn, not the existence of such protection. Take the example of two adjacent Pawns on, say, d4 and e4. Neither protects the other but each as the ability to be guarded by the other, by advancing. We must therefore say that the weakness or strength of two adjacent Pawns depends on whether or not they are able to advance if the necessity arises... The most common form of Pawn weakness encountered in practical play is the isolated Pawn - one which has lost its neighbors and stands alone in face of the enemy. Such a Pawn has two basic deficiencies: firstly it requires defense, and secondly the squares immediately in front of it make ideal outposts for the other player."

Here we see evidence that to effectively evaluate pawns, we need to consider 1) the restrictions they impose on the mobility of pieces (friendly and enemy), and 2) how attackable they are.

p.51"the White Pawns provide a very effective barrier against the enemy Bishop without any way impeding their own Bishop.  Above all there is no question of White having any weak Pawns [in the game being discussed] - they all protect each other, except for the 'base' at c2 which is completely unassailable."

Traditional chess programs that give a bonus to rooks for sitting on open files are likely to award this bonus without checking to see that there is an entry point for such a piece after a potential movement down the file in question. Stean thinks that without an entry point that there is no value to such a positional rook move. 

p.66-67,78-79" 'Put your rooks on open files' is a piece of advice every beginner receives, and a very sound piece of advice it is. But like all pieces of sound advice, it can prove to be inadequate, or worse... Occupation of an open file is of no value unless there is a chance of penetration... It must be stressed that open files only have a value as a means of feeding Rooks (or [possibly] Queens) into the enemy position, so that a file has no value unless there is somewhere along it an entry point, i.e., an advanced point on which a Rook can safely land... To summarize, the use of open files can be broken down into three parts: (i) Take control of the file. (ii) Find a point of entry (this is the important part; without an entry point a file has no value). (iii) Penetrate via the entry point."

In order to properly evaluate the strengths of the pieces, it seems that we need to find a way to estimate how a piece 'pulls its weight' in a position by exerting pressure on objectives.

p.71"Chess is very much a team game. The pieces rely heavily on each other's help and cooperation, so if one does not pull its weight it lets the whole side down."

Mobility and space are important, but how do we define space? It is not a stretch to suggest that space allows pieces to trace future mobility towards objectives. Future mobility is a measure of space and the first step in forming plans to attack enemy weaknesses. It seems that tactical opportunities multiply as we focus our search efforts on (1) ways to move pieces towards weaknesses in the enemy position and (2) ways to restrict the enemy's ability to resist the advances.

p.132"The essence of simple chess is mobility. Pieces need to be kept active and used economically. All the objectives of simple chess can be traced back to this underlying notion... weak Pawns hamper mobility because they require protection... However, the single most important factor in determining mobility must be space, but what is space? ...space is not an easily definable or recognizable concept... The following is nearer the truth. Any given Pawn structure has a certain capacity for accommodating pieces efficiently. Exceed this capacity and the pieces get in each other's way, and so reduce their mutual activity." 

This is how Stean would exploit a space advantage. Note that one measure of 'counterplay' is the future mobility of the pieces, modified by the limiting factors which exist on the board and which conspire to restrict this mobility.

p.140"The strategy behind playing to exploit a space advantage is twofold:

   (i) Deprive the opponent of any counter-play, avoiding exchanges whenever possible. The psychological pressure of being permanently hemmed in may well induce him to weaken himself in order to gain some freedom.

   (ii) If no weaknesses are forthcoming you must be prepared to attack on either wing. Greater space control gives you better communication between flanks, so you naturally want to exploit this fact to build up against the adversary's weaker front."

According to Stean's definition of space advantage below, it is difficult to determine whether or not this condition exists unless your evaluation function takes into account the restrictions placed on the mobility of the pieces by the pawn structure (and of course other pieces)

p.157"The real criterion [for a space advantage] is whether your opponent has more pieces than can comfortably fit in with his Pawn structure"

-------------------------------------------------------------------------------------

Simple Chess, Michael Stean

Source

http://johnljerz.com/superduper/tlxdownloadsiteMAIN/id143.html