The player controlling the white pieces is named "White"; the player controlling the black pieces is named "Black". White moves first, then players alternate moves. Making a move is required; it is not legal to skip a move, even when having to move is detrimental. Play continues until a king is checkmated, a player resigns, or a draw is declared, as explained below. In addition, if the game is being played under a time control, a player who exceeds the time limit loses the game unless they cannot be checkmated. The official chess rules do not include a procedure for determining who plays White. Instead, this decision is left open to tournament-specific rules (e.g. a Swiss system tournament or round-robin tournament) or, in the case of non-competitive play, mutual agreement, in which case some kind of random choice is often employed. A common method is for one player to conceal a piece (usually a pawn) of each color in either hand; the other player chooses a hand to open and receives the color of the piece that is revealed.
Each type of chess piece has its own method of movement. A piece moves to a vacant square except when capturing an opponent's piece. Except for any move of the knight and castling, pieces cannot jump over other pieces. A piece is captured (or taken) when and only when an attacking enemy piece replaces it on its square except in the case of en passant. The captured piece is thereby permanently removed from the game. The king can be put in check but cannot be captured (see below).
- The king moves exactly one square horizontally, vertically, or diagonally. A special move with the king known as castling is allowed only once per player, per game (see below).
- A rook moves any number of vacant squares horizontally or vertically. It also is moved when castling.
- A bishop moves any number of vacant squares diagonally.
- The queen moves any number of vacant squares horizontally, vertically, or diagonally.
- A knight moves to one of the nearest squares not on the same rank, file, or diagonal. (This can be thought of as moving two squares horizontally then one square vertically, or moving one square horizontally then two squares vertically—i.e. in an "L" pattern.) The knight is not blocked by other pieces; it jumps to the new location.
- Pawns have the most complex rules of movement:
- A pawn moves straight forward one square, if that square is vacant. If it has not yet moved, a pawn also has the option of moving two squares straight forward, provided both squares are vacant. Pawns cannot move backwards.
- A pawn, unlike other pieces, captures differently from how it moves. A pawn can capture an enemy piece on either of the two squares diagonally in front of the pawn. It cannot move to those squares when vacant except when capturing en passant.
Castling consists of moving the king two squares towards a rook, then placing the rook on the other side of the king, adjacent to it. It is not allowed to move both king and rook in the same time, because "Each move must be played with one hand only. Castling is only permissible if all of the following conditions hold:
- The king and rook involved in castling must not have previously moved;
- There must be no pieces between the king and the rook;
- The king may not currently be in check, nor may the king pass through or end up in a square that is under attack by an enemy piece (though the rook is permitted to be under attack and to pass over an attacked square);
- The castling must be kingside or queenside.
When a pawn advances two squares from its original square and ends the turn adjacent to a pawn of the opponent's on the same rank, it may be captured by that pawn of the opponent's, as if it had moved only one square forward. This capture is only legal on the opponent's next move immediately following the first pawn's advance. The diagrams on the right demonstrate an instance of this: if the white pawn moves from a2 to a4, the black pawn on b4 can capture it en passant, moving from b4 to a3 while the white pawn on a4 is removed from the board.
If a player advances a pawn to its eighth rank, the pawn is then promoted (converted) to a queen, rook, bishop, or knight of the same color at the choice of the player (a queen is usually chosen). The choice is not limited to previously captured pieces. Hence it is theoretically possible for a player to have up to nine queens or up to ten rooks, bishops, or knights if all of their pawns are promoted. If the desired piece is not available, the player must call the arbiter to provide the piece.
A king is in check when it is under attack by at least one enemy piece. A piece unable to move because it would place its own king in check (it is pinned against its own king) may still deliver check to the opposing player. It is illegal to make a move that places or leaves one's king in check. The possible ways to get out of check are:
- Move the king to a square where it is not in check.
- Capture the checking piece (possibly with the king).
- Block the check by placing a piece between the king and the opponent's threatening piece.
If it is not possible to get out of check, the king is checkmated and the game is over (see the next section). In informal games, it is customary to announce "check" when making a move that puts the opponent's king in check. However, in formal competitions, check is rarely announced
End of the game
If a player's king is placed in check and there is no legal move that player can make to escape check, then the king is said to be checkmated, the game ends, and that player loses (Schiller 2003:20–21). Unlike other pieces, capturing the opponent's king is not allowed.The diagram shows an example checkmate position. The white king is threatened by the black queen; the square to which the king could move is also threatened; it cannot capture the queen, because it would then be in check by the rook.
Either player may resign at any time, conceding the game to the opponent. A player may resign by saying it verbally or by indicating it on the score sheet in any of three ways: (1) by writing "resigns", (2) by circling the result of the game, or (3) by writing "1–0" if Black resigns or "0–1" if White resigns (Schiller 2003:21). Tipping over the king also indicates resignation, but it should be distinguished from accidentally knocking the king over. Stopping both clocks is not an indication of resigning, since clocks can be stopped to call the arbiter. An offer of a handshake is sometimes used, but it could be mistaken for agreement to a draw.
Illegal move in Blitz
In Blitz chess, if a player completes an illegal move, the player's opponent may claim a win before making a move (if the opponent has enough material to win). One way to claim this win is to take a King left in check by the opponent. Once the illegal move has been answered, the move stands.
A dead position is defined as a position where neither player can win the game by any sequence of legal moves.
- Any positions with the following pieces only are known as dead positions. The USCF rules speak of insufficient material for these positions:
- king against king;
- king against king and bishop;
- king against king and knight;
- king and bishop against king and bishop, with both bishops on squares of the same color.
- However, insufficient material is not the only condition for a dead position. There are positions where the pieces on the board would be sufficient to mate if arranged otherwise.
The game ends in a draw if any of these conditions occur:
- The game is automatically a draw if the player to move is not in check and has no legal move. This situation is called a stalemate. An example of such a position is shown in the adjacent diagram.
- The game is immediately drawn for a dead position.
- Both players agree to a draw after one of the players makes such an offer.
- The player having the move may claim a draw by declaring that one of the following conditions exists, or by declaring an intention to make a move which will bring about one of these conditions. If the claim is proven true, the game is drawn:
- The same board position has occurred three times with the same player to move and all pieces having the same rights to move, including the right to castle or capture en passant.
- There has been no capture or pawn move in the last fifty moves by each player, if the last move was not a checkmate.
- The game ends immediately with a draw by the intervention of the arbiter, without a draw request necessary:
- When the same board position has occurred five times.
- When the moves without capture or pawn move extend up to seventy-five.
A game played under time control will end as a loss for a player who uses up all of the time allotted on the player's clock, which is called flag-fall, unless the opponent has no possibility of effecting checkmate (see Timing). There are different types of time control. A player may have a fixed amount of time for the entire game, or may have to make a certain number of moves within a specified time. Also, a small increment of time may be added for each move made.