Chess/Playing The Game
Chess, unlike many other games, does not involve direct chance such as the roll of a dice or which card is drawn. The outcome completely depends on the decisions of the players. However, because of its vast complexity, the far-reaching consequences of some decisions are practically unforeseeable.
One player ("White") has the white pieces while the other ("Black") has the black pieces. Sometimes the colors are not black and white (for instance, light and dark, or yellow and blue), but they generally contrast each other. In friendly games the choice of colors can be made by any method, such as flipping a coin. If there is no coin at hand, another typical way of deciding would be to conceal a black piece in one hand and a white piece in the other and ask one's opponent to select a hand. The colored piece selected will be the opponent's color. In competitive games the players are assigned their colors.
Order of play 
Once all the pieces have been arranged, White (or the lighter color) makes the first move. White always makes the first move; this is important for notation, and any chess player will insist upon it. After White has made the move, Black will then make a move. The gameplay will continue in alternating fashion, White making a move, followed by Black.
General movement rules 
- A move consists of moving a single piece, in accordance with its rules of movement, to a square that is unoccupied or occupied by an enemy piece. A player may never move a piece onto a square already occupied by another of his or her own pieces.
- Exception: There is a special move called "castling" where two pieces, a rook and the king, are moved; see below.
- If a piece is moved onto a square occupied by an enemy piece, the latter piece is removed from play and the first piece replaces it. The removed piece is said to have been captured or taken.
- Exception: In en passant capture, a pawn moves to an unoccupied square but still captures another pawn "in passing"; see below.
- Most pieces move and capture opponent pieces in the same way.
- Exception: The pawn has separate rules for moving and capturing opponent pieces.
- Most pieces may only make a move to a non-adjacent square if all the intervening squares are vacant (pieces may not 'jump over' other pieces).
- Exception: The knight can move to any suitable final square regardless of occupants of other squares.
- Exception: In castling, a king and a rook jump over each other.
- No player may make a move that leaves their king "in check" (see below).
- The player must always make a move when it is his or her turn. In other words, he or she cannot choose not to make a move. If no legal move is possible the game ends in a draw (see below), except when the king is in check - this is called checkmate, and is usually how the opposing player wins.
Also, when a pawn moves to a square at the opposite end of the board, it becomes a different piece (pawn promotion); all of these exceptions are covered below in more detail.
The board 
Traditionally, the game is played on a board of 64 alternating black and white squares turned with a white square to each player's near right-hand corner. "White on right" is a helpful saying to remember this convention. The light and dark squares on the chessboard and the light and dark chess pieces are traditionally referred to as "white" and "black" respectively, although in modern chess sets almost any colors may be used (as long as they are not the same colors.)
The horizontal rows of squares are called ranks and are numbered 1-8; the vertical columns of squares are called files and given the letters a-h. This way any single square can be easily identified by its rank and file, making it possible to record games by writing down the starting and ending position of the piece that moves every turn.
A chess diagram is always printed from the White player's perspective.
The pieces 
The movement of the individual pieces is described below. In all the board diagrams shown, the squares to which the piece in question can move are indicated with x's.
Pawns can move one square straight forward, or optionally and on their first move only, two squares straight forward. The pawn is the only piece that can't move backwards.
Capturing Pieces 
The pawn can move one square diagonally forward to capture a piece, but cannot capture a piece by moving straight forward. For this reason, two opposing pawns on a file may become blocked by each other. In the first diagram below, legal capture moves for the white pawn is indicated with black circles.
In the second diagram below the White pawn is prevented from moving forwards by the Black pawn immediately in front of it (in the d-file) which it cannot capture, but it can capture the adjacent Black pawn by moving diagonally forward as seen in the last diagram.
The pawn is the only piece that moves and captures differently.
The knight has a unique L-shaped move; two squares in one direction either horizontally or vertically, and one square in another direction perpendicular to the first. The knight moves directly to the destination square, and may jump over any pieces blocking its way. The knight is the only piece that may always jump over or "move between" other pieces (another exception is the castling move). It is also the only piece that can't stop at the squares it moves over.
The Knight is the chess piece with the most complex movement to understand. Thus there are many ways to look at and remember the Knight's movement:
Capturing Pieces 
The knight captures any opponent's piece that it lands on at the end of its L (or Y) shaped move. In the diagrams below the knight may take any of the black queens.
The bishop can move any number of squares diagonally. The bishop may not jump over any piece of either color.
The bishop is restricted to the color of squares on which it began the game. Each player starts out with one light-square bishop that moves on the light colored squares, and one dark-square bishop that moves on the dark colored squares. In the diagram below, the bishop stands on a light square and can only move to other light squares.
Capturing Pieces 
The bishop captures any opponent's piece that it encounters during the movement described above, and then occupies the captured piece's square. In the diagram above the bishop may take any of the black queens. Notice that bishop may not move (jump) to squares behind or capture pieces hiding behind the queens.
The rook can be moved any number of squares horizontally or vertically, but not diagonally. Like the bishop, the rook cannot jump over any pieces, except for "castling".
Capturing Pieces 
If the rook attempts to occupy a space already occupied by an opponent's piece, it captures the piece. In the diagram above the rook may take any of the black queens.
The queen is the most powerful piece, being able to move any number of squares in any lateral or diagonal direction. It is best described as the combination of a rook's and bishop's movement capabilities.
Capturing Pieces 
The queen captures any opponent's piece that it encounters during the movement described above, and then occupies the captured piece's square. In the diagram above the queen may take any of the black queens.
The king can move one square at a time in any direction, as long as doing so does not place himself in check (see below).
Capturing Pieces 
The king may capture any opponent's piece adjacent to it, as long as doing so does not place himself in check (see below). In the diagrams above the king may take any of the black knights.
The king is the most important piece belonging to each player, though not the most powerful. If a player moves a piece such that he threatens to capture his opponent's king in the next move, that king is said to be in check.
If a player's king is in check, he must immediately remove the check by moving the king, blocking the check with another piece, or capturing the checking piece.
In the diagram below black's rook has checked the white king. White may avoid the check by moving the king one step sideways, blocking the check by putting the rook between the attacking black rook and the white king, or capture the black rook using the white bishop. Other normally legal moves, like moving one of the pawns, are illegal in this position since they will not remove the check.
In a friendly game a check is usually announced by saying check after the move is completed.
If the king is placed in check and can not escape, it is said to have been checkmated (or "mated" for short). The first player to checkmate the opponent's king wins the game. Note that the king is never actually captured, since it is obliged to move out of check whenever possible (and the game ends when it is impossible). In the diagram below white has no options to escape the check from black's rook, he is therefore checkmated.
Special Restrictions — Avoiding "Self-check" 
Players may not make any move which allows their king to be captured in the next move, i.e. places their own king in check. Thus two kings may never occupy adjacent squares, since they would have put themselves in check by moving there. This is called the "opposition" and is indispensable when, for instance, you are using a queen or rook to checkmate a king.
The White king in the following diagram cannot move upwards or to the left since it would be in check from the bishop, or diagonally downwards which would leave it adjacent to the Black king. Also, as no piece is threatening it if it fails to move, the king is not currently in check. Similarly, the Black king cannot move diagonally upwards as that would put it next to the White king.
The diagram below shows a position where the white bishop's movement is restricted by the same rule; the bishop can not be moved since the move would let black capture the white king in his next move. The white king on the other hand may move to any of the adjacent squares.
Special Moves 
Pawn Promotion 
If a pawn makes it to one of the eight squares along the far edge of the board from their initial position, the pawn is "promoted". Upon reaching the far rank the player exchanges the pawn with either a queen, a rook, a bishop, or a knight. The player's move ends when the new piece occupies the promoted square.
The new piece need not be a previously captured piece. Thus a player can have more than one queen, and more than two rooks, bishops or knights on the board. The player may never have more than one king, since the pawn can not be promoted to a king. In theory it is possible to get up to nine queens, or ten rooks, bishops or knights since there are eight pawns to promote. In practice however the pawn is usually promoted to a queen, since it is the most powerful piece, and it is rare for a player to have more than two queens on the board. If an extra queen is not at hand, a upside-down rook is usually used as a substitute.
Castling is a move involving the king and either of the rooks. Castling performed with the king's rook is called kingside castling, performed with the queen's rook is called queenside castling. A castling is typically done to move the king to a protective 'castle' surrounded by three pawns and a rook.
Subject to restrictions detailed below, a player may move his king two squares towards the rook, and subsequently, on the same turn, move the rook adjacent to but on the opposite side of the king, (onto the square over which the king has just passed).
The restrictions specific to castling are:
The diagrams below shows example of positions where castling is not legal.