Chess strategy
Chess is a highly strategic game. Chess experts tend to divide the study of chess strategy into two different categories: strategy and tactics, and into three distinct phases: the opening, middle game, and endgame. Tactics might be described as short-term strategy; it involves studying maneuvers, such as combinations, and how those maneuvers might lead to a gain in material or improvements in a player's strategic position. The word strategy in chess refers to the study of long-term improvements to a player's position, such as control of the center of the board, protection of the king, pawn structure, placement of the pieces, and other considerations.
Material
In the game of chess, some pieces are considered more valuable than others. As a result, much of strategy in chess centers around trying to gain an advantage in "material". This is accomplished by having more pieces, or more valuable pieces on the board. In the study of chess, the pieces are assigned a point value:
Pawns are worth 1 point "Minor" pieces, Bishops and Knights are worth 3 points Rooks are worth 5 points The Queen is worth 9 points.
Much of the study of tactics revolved around the value of material; a player will not trade off a queen for two bishops, even though they would have more pieces on the board, because the pieces left would have less value.
The point values are also relative; for example, in endgames with pawns on only one side of the board, knights are often preferred to bishops, because a bishop can only operate on squares of their color, while in endgames with pawns on both sides, a bishop is often preferred, because they can move more quickly to both sides of the board. Having 2 bishops is also generally considered better than having a knight and a bishop or 2 knights, because the bishops can work together by attacking both colors of squares.
Tactics
Opening Strategy
Openings are extremely important in the game of chess. There are volumes of chess literature devoted solely to the study of a certain sets of moves: the Spanish, the Italian, the Sicialian, the French, the English, etc. are all different sets of opening moves.
Clasical Opening strategy tends to center around several strategic principles. First, a player should attempt to control and occupy the center of the board with their pieces. Secondly, a player should attempt to make their position more free, by allowing their pieces space to operate in. Thirdly, a player should try to castle, so that their king is out of the center of the board and protected, and so that their rook is moved out of the corner and can be more useful.
Another school of thought, known as "hypermodern" opening theory, disputes the idea that a player must occupy the center of the board to be effective. In this school of thought, a player is encouraged to control the center by controlling the sides, and allowing the opponent to overextend himself in the center of the board, setting up a counterattack. Many of the Sicilian (1.e4 c5), English (c4) and Reti (1.Nf3 d5 2. c4) systems are considered hypermodern, or are derived from hypermodern theory.
Middlegame Strategy
The middlegame in chess is very complicated, but very little chess literature is dedicated to it. It generally centers around both players trying to find room for their pieces. Sometimes one player will attack the other's position. Also, both players will try to get their rooks onto open, or half-open files; an open file is a column of squares in which neither player has a pawn, while a half-open file is one in which only the opponent has a pawn. Both allow the rook more freedom in transitioning to the endgame, and may allow the rook to invade the opposing position.
Endgame Strategy
The endgame is when most of the pieces are traded off, and each player attempts to win, generally by forcing a promotion of a pawn to a queen. The type of endgame is generally defined by the pieces still remaining on the board.
King and Pawns: These are the most common endings, because the rooks are located in the corners of the board to begin with, so they usually take awhile to enter the game. Having a rook "on the seventh" or located on the row where the opponents pawns began is often advantageous in rook and pawn endings, as undefended pawns can be attacked.
Piece and Pawns: These endings happen when there are one or more "minor" pieces (bishops and knights). Having 2 bishops is often preferable to any other combination of pieces, as they can attack both colors.
King and Pawns: These endings occur when all of the pieces except the kings have been traded off. They are considered extremely "sharp", in that one wrong move will usually cost a player the game. In many cases, an advantage of a single pawn is sufficient to force a win. Many of these endings also come down to "tempo", or which player is forced to move first.
Queen and Pawns: Queen and pawn endings occur when there are still queens left on the board. In these endings, the protection of one's king is of paramount importance; if the king is not protected, a player can be repeatedly placed in check by the opposing queen. In Queen and pawn endings a "passed" pawn, or a pawn which cannot be stopped by other pawns, can be extremely powerful. The player that has passed his pawn can force the enemy queen away, because if the queens are traded, the only piece left to stop the advance of the pawn is the opposing king.