Rules of chess
Chess is a game, played by two players. One player plays with the white pieces, and the other player plays with the black pieces. Each player has sixteen pieces in the beginning of the game: one king, one queen, two rooks, two bishops, two knights, and eight pawns.
From the view of the white player, the rows are numbered 1, 2, 3, 4, 5, 6, 7, 8; the lowest row has number 1, and the upper row has number 8. The columns are named, from left to right, a, b, c, d, e, f, g, h. A square gets a name, consisting of the combination of its column-letter and row-number, e.g., the square in the lower left corner (for white) is a1.
Alternately, the players make a move, starting with the white player (the player that plays with the white pieces.) A move consists of moving one of the pieces of the player to a different square, following the rules of movement for that piece - there is one special exception, named castling, where players move two pieces simultaneously.
A player can take a piece of the opponent by moving one of his own pieces to the square that contains a piece of the opponent. The opponents piece then is removed from the board, and out of play for the rest of the game. (Taking is not compulsory.)
Movement of the pieces
The rook moves in a straight line, horizontally or vertically. The rook may not jump over other pieces, that is: all squares between the square where the rook starts its move and where the rook ends its move must be empty. (As for all pieces, when the square where the rook ends his move contains a piece of the opponent, then this piece is taken. The square where the rook ends his move may not contain a piece of the player owning this rook.)
The bishop moves in a straight diagonal line. The bishop may also not jump over other pieces.
The queen has the combined moves of the rook and the bishop, i.e., the queen may move in any straight line, horizontal, vertical, or diagonal.
The knight makes a move that consists of first one step in a horizontal or vertical direction, and then one step diagonally in an outward direction. The knight jumps: it is allowed that the first square that the knight passes over is occupied by an arbitrary piece. For instance, white can start the game by moving his knight from b1 to c3. The piece that is jumped over is further not affected by the knight: as usual, a knight takes a piece of the opponent by moving to the square that contains that piece.
The pawn moves differently regarding whether it moves to an empty square or whether it takes a piece of the opponent. When a pawn does not take, it moves one square straight forward. When this pawn has not moved at all, i.e., the pawn is still at the second row (from the owning players view), the pawn may make a double step straight forward. For instance, a white pawn on d2 can be moved to d4. When taking, the pawn goes one square diagonally forward.
A double pawn step, and a following en-passant capture
The king moves one square in any direction, horizontally, vertically, or diagonally. There is one special type of move, made by a king and rook simultaneously, called castling: see below.
Under certain, special rules, a king and rook can move simultaneously in a castling move.
The king that makes the castling move has not yet moved in the game.
When castling, the king moves two squares towards the rook, and the rook moves over the king to the next square, i.e., black's king on e8 and rook on a8 move to: king c8, rook d8 (long castling), white's king on e1 and rook on h1 move to: king g1, rook f1 (short castling).
Check, mate, and stalemate
When the king of a player can be taken by a piece of the opponent, one says that the king is in check. For instance, the white player moves his rook to a position such that it attacks the black king, i.e., if black doesn't do anything about it, the rook could take the black king in the next move: we say that the white rook gives check. It is considered good manners to say check when one checks ones opponent.
It is not allowed to make a move, such that ones king is in check after the move. If a player accidently tries to make such a move, he must take the move back and make another move (following the rules that one must move with the piece one has touched)
When a player is in check, and he cannot make a move such that after the move, the king is not in check, then he is mated. The player that is mated lost the game, and the player that mated him won the game.
Note that there are three different possible ways to remove a check:
1. Move the king away to a square where he is not in check.
2. Take the piece that gives the check.
3. (In case of a check, given by a rook, bishop or queen: ) move a piece between the checking piece and the king.
When a player cannot make any legal move, but he is not in check, then the player is said to be stalemated. In a case of a stalemate, the game is a draw.
Resign and draw proposals
A player can resign the game, which means that he has lost and his opponent has won.
Repetition of moves
If the same position with the same player to move is repeated three times in the game, the player to move can claim a draw. (When the right to make a certain castling move is lost by one of the players between positions, then the positions are considered to be different)
50 moves rule
If there are have been 50 consecutive moves of white and of black without any piece taken or any pawn move, then a player can claim a draw.
When a player touches one of his own pieces, he must, if possible, make a legal move with this piece. When a player touches a piece of the opponent, he must, if possible, take this piece.
Chess clocks and time
Often, players play the game with chess clocks. These clocks count the time that each player separately takes for making his own moves. Additional rules are then used, saying how many (possibly all) moves must be made before a player has used a certain time for his moves.