Rules of chess

Moves of the king a b c d e f g h 8 8 7 7 6 6 5 5 4 4 3 3 2 2 1 1 a b c d e f g h

Moves of a rook a b c d e f g h 8 8 7 7 6 6 5 5 4 4 3 3 2 2 1 1 a b c d e f g h

Moves of a bishop a b c d e f g h 8 8 7 7 6 6 5 5 4 4 3 3 2 2 1 1 a b c d e f g h

Moves of the queen a b c d e f g h 8 8 7 7 6 6 5 5 4 4 3 3 2 2 1 1 a b c d e f g h

Moves of a knight a b c d e f g h 8 8 7 7 6 6 5 5 4 4 3 3 2 2 1 1 a b c d e f g h

Moves of a pawn a b c d e f g h 8 8 7 7 6 6 5 5 4 4 3 3 2 2 1 1 a b c d e f g h The pawns can move to the squares marked "×" in front of them. The pawn on c6 can also take either black rook.

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 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.[3] 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.

The pawn is also involved in the two special moves en passant and promotion.[4]

a b c d e f g h 8 8 7 7 6 6 5 5 4 4 3 3 2 2 1 1 a b c d e f g h Position of pieces before castling

a b c d e f g h 8 8 7 7 6 6 5 5 4 4 3 3 2 2 1 1 a b c d e f g h Positions of the king and rook after kingside (White) and queenside (Black) castling

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."[6] Castling is only permissible if all of the following conditions hold:[7]

• 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 under attack, 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 as shown in the diagram.

An unmoved king and an unmoved rook of the same color on the same rank are said to have castling rights.

en passant

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 en passant 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.[8][9]

	a	b	c	d	e	f	g	h
8									8
7									7
6									6
5									5
4									4
3									3
2									2
1									1
	a	b	c	d	e	f	g	h

Black's king is in check. It can get out of check by moving to an unattacked square. Black can also parry the check by moving the bishop to e5 or the knight to f4 to block the check, or by capturing the white bishop with the knight.[10]

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.[11][12][13]

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.[14]

	a	b	c	d	e	f	g	h
8									8
7									7
6									6
5									5
4									4
3									3
2									2
1									1
	a	b	c	d	e	f	g	h

White is checkmated; Black wins.[15]

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.[16] Unlike other pieces, the king is never captured.[17]

The diagram shows an example checkmate position. The white king is threatened by the black queen; the empty square to which the king could move is also threatened; and the king 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.[18] 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 a draw offer.[19]

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.[20]

	a	b	c	d	e	f	g	h
8									8
7									7
6									6
5									5
4									4
3									3
2									2
1									1
	a	b	c	d	e	f	g	h

Black to move is in stalemate, since Black's king has no legal move, and is not in check. The game is drawn.[21]

The game ends in a draw if any of these conditions occur:

• 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 reaches a dead position.
• Both players agree to a draw after one of the players makes such an offer.
• The player having the move claims a draw by correctly declaring that one of the following conditions exists, or by correctly declaring an intention to make a move which will bring about one of these conditions:[22]
  • 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 (see threefold repetition rule).
  • There has been no capture or pawn move in the last fifty moves by each player, if the last move was not a checkmate (see fifty-move rule).
• The arbiter intervenes to declare a draw, without a draw request necessary:
  • When the same board position has occurred five times (see fivefold repetition rule).
  • When the moves without capture or pawn move extend up to seventy-five (see seventy-five-move rule).

At one time, if a player was able to check the opposing king continually (perpetual check) and the player indicated their intention to do so, the game was drawn. This rule is no longer in effect; however, players will usually agree to a draw in such a situation, since either the rule on threefold repetition or the fifty-move rule will eventually be applicable.[23][24]

Example of a dead position[25]

	a	b	c	d	e	f	g	h
8									8
7									7
6									6
5									5
4									4
3									3
2									2
1									1
	a	b	c	d	e	f	g	h

White has just played h5; neither side can open up the position.

A dead position is defined as a position where neither player can checkmate their opponent's king by any sequence of legal moves.[26]

• Any positions with only the following pieces are dead positions, and are known as draws by insufficient material:[28]
  • 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 (see King and two bishops).
• However, insufficient material is not the only condition for a dead position. There are positions in which checkmate is impossible but the pieces on the board would be sufficient to mate if arranged otherwise. This usually occurs in blocked king and pawn endings where it is impossible for either king to capture the pawns. See the diagram "Example of a dead position".

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.

The movement of pieces is to be done with one hand. Once the hand is taken off a piece after moving it, the move cannot be retracted unless the move is illegal.[30] As for the touch-move rule, an arbiter who observes a violation of this rule must intervene immediately.[31] A player must claim a violation of the rule immediately before making a move, or lose the right to claim.[32]

When castling, a player should first move the king with one hand and then move the rook with the same hand.[33]

In the case of a promotion, if a player releases the pawn on the eighth rank, the player must promote the pawn. After the pawn has moved, the player may touch any piece not on the board and the promotion is not finalized until the new piece is released on the promotion square.[34]

In serious play, if a player having the move touches a piece as if having the intention of moving it, then the player must move it if it can be legally moved. So long as the hand has not left the piece on a new square, any legal move can be made with the piece. If a player touches one of the opponent's pieces then that piece must be captured if there is a legal move that does so. If none of the touched pieces can be moved or captured, there is no penalty.[35] An arbiter who observes a violation of this rule must intervene immediately.[31] A player must claim a violation of the rule immediately before making a move, or lose the right to claim.[32]

When castling, the king must be the first piece touched.[36] If the player touches the king and a rook, the player must castle with that rook if it is legal to do so.[37] If the player completes a two-square king move without touching a rook, the player must move the correct rook accordingly if castling in that direction is legal. If a player starts to castle illegally, another legal king move must be made if possible, including castling with the other rook.[38]

If a player moves a pawn to its eighth rank, it cannot be substituted for a different move of the pawn when the player has stopped touching it. However, the move is not complete until the promoted piece is released on that square.

If a player touches a piece to adjust its physical position within a square, he must first alert his opponent by saying J'adoube or "I adjust".[39] Once the game has started, only the player with the move may touch the pieces on the board.[40]

Digital chess clock

Tournament games are played under time constraints, called time controls, using a chess clock. Each player is timed separately and must make moves within the time control or forfeit the game. There are different types of time controls applied. For standard chess, different periods can be defined with different fixed times (e.g. first 40 moves in 100 minutes, next 20 moves in 50 minutes, remaining moves in 15 minutes). For rapid and blitz chess, only one period can be defined where all moves must be performed. Additionally, an increment or delay per move may be defined.[41]

• When a player runs out of time, this event is called flag fall. A flag fall has no consequences unless stated as observed by the arbiter, in which case the arbiter must intervene,[42] or claimed by a player.[43]
• When no flag fall is stated, and one of the following events occur, the result of the game still holds. It is of no relevance if the player runs out of time afterwards, or has already run out of time, but this was not stated:
  • If a player delivers a checkmate, the game is over and that player wins.[44]
  • If a move results in a stalemate, dead position, fivefold repetition or the seventy-five-move rule applies, the game is over and the game is drawn.[45]
• If a player correctly claims flag fall, that player wins. But if the claiming player is out of time, or could not still theoretically checkmate the opponent, the game is a draw.[46]

The United States Chess Federation (USCF) rule is different. USCF Rule 14E defines "insufficient material to win on time", that is lone king, king plus knight, king plus bishop, and king plus two knights opposed by no pawns, and there is no forced win in the final position. Hence to win on time with this material, the USCF rule requires that a win can be forced from that position, while the FIDE rule merely requires a win to be possible. (See Monika Soćko rules appeal in 2008 and Women's World Chess Championship 2008 for a famous instance of this rule.)

• With mechanical clocks only, flag fall for both players can occur. With digital clocks, the clock indicates which flag fell first, and this information is valid.[47]
• If a flag fall is stated, and as can happen with mechanical clocks only, the flag fall happened for both players, then:[48][50]
  • If it can be established which player ran out of time first, the rules apply for flag fall for one player only.
  • Otherwise, the result is a draw, unless this is a standard chess game which is not in the last period, here the play will be resumed.

In the last period of a standard chess game or rapid games, if played without increment, a special set of rules applies regarding the clock, referenced as "Quickplay Finishes".[51] These rules allow a player with under two minutes time to request an increment introduced, or request a draw based on claiming no progress or no effort, to be ruled by the arbiter. These rules have been relevant when playing with mechanical clocks, which do not allow setting an increment and are today with digital clocks of second importance only, as playing with increment is recommended.[52]

Naming the squares in algebraic notation

A score sheet from a game by José Raúl Capablanca, in descriptive notation

Each square of the chessboard is identified with a unique pair of a letter and a number. The vertical files are labeled a through h, from White's left (i.e. the queenside) to White's right. Similarly, the horizontal ranks are numbered from 1 to 8, starting from the one nearest White's side of the board. Each square of the board, then, is uniquely identified by its file letter and rank number. The white king, for example, starts the game on square e1. The black knight on b8 can move to a6 or c6.

In formal competition, each player is obliged to record each move as it is played in algebraic chess notation in order to settle disputes about illegal positions, overstepping time control, and making claims of draws by the fifty-move rule or repetition of position. Moves recorded in any other systems of notation cannot be used in evidence in such a dispute. Other chess notation systems include ICCF numeric notation for international correspondence chess and descriptive chess notation, formerly standard in English speaking countries. The current rule is that a move must be made on the board before it is written on paper or recorded with an electronic device.[53][54][55]

Both players should indicate offers of a draw by writing "=" at that move on their score sheets.[56] Notations about the time on the clocks can be made. A player with less than five minutes left to complete all the remaining moves is not required to record the moves (unless a delay of at least thirty seconds per move is being used). The score sheet must be made available to the arbiter at all times. A player may respond to an opponent's move before writing it down.[57]

See Adjournment § Chess.

Formerly common, adjournments are no longer standard practice in chess competition.

When an adjournment is made, the player whose move it is writes their next move on their scoresheet but does not make the move on the chessboard. This is referred to as a sealed move. Both opponents' scoresheets are then placed in the sealed-move envelope and the envelope is sealed. The names of the players, the colors, the position, the time on the clocks and other game data are recorded on the envelope; the envelope may also be signed by both players. The arbiter then keeps possession of the envelope until it is time to restart the game, at which time the arbiter opens the envelope, makes the sealed move on the board, and starts the opponent's clock.

An illegal move[58] is a move not made according to a piece's possible defined movements [59] or made according to its possible movements but such that its own king is left or placed in check.[60] Furthermore, pressing the clock without making a move or making a move with two hands is considered and penalized as an illegal move.[61]

A player who makes an illegal move must retract that move and make a legal move. That move must be made with the same piece if possible, because the touch-move rule applies. If the illegal move was an attempt to castle, the touch-move rule applies to the king but not to the rook. If the mistake is noticed, the game should be restarted from the position in which the error occurred. The arbiter should adjust the time on the clock according to the best evidence.[62] Some regional organizations have different rules.[63][64]

A player may correct an illegal move if the player has not pressed the clock. If a player has pressed the clock, the illegal move may be stated by the arbiter intervening or by the opponent claiming the illegal move. In Standard chess, the illegal move must be claimed before the end of the game.[62] In the most used form of Rapid chess and Blitz chess, if the arbiter does not intervene and the opponent moves, the illegal move is accepted and without penalty.[65][66]

According to the FIDE Laws of Chess, the first stated completed illegal move results in a time penalty. The time penalty consists of giving the opponent two minutes extra time in standard and rapid chess, one minute extra time in Blitz.[67] The second stated completed illegal move by the same player results in the loss of the game,[68] unless the position is such that it is impossible for the opponent to win by any series of legal moves (e.g. if the opponent has a bare king) in which case the game is drawn.[46] A move is completed when it has been made and the player has pressed the clock.[69]

For Standard chess and the most used form of Rapid and Blitz chess there are the following rules. If it is discovered during the game that the starting position was incorrect, the game is restarted. If it is discovered during the game that the board is oriented incorrectly, the game is continued with the pieces transferred to a correctly oriented board. If the game starts with colours reversed, the game is restarted if less than 10 moves have been made by both players, otherwise the game is continued.[70] If the clock setting is found to be incorrect during the game, it is corrected according to best judgement.[71] Some regional organizations have different rules.[72][73]

If a player knocks over pieces, it is the same player's responsibility to restore them to their correct positions, on that player's time. If it is discovered that an illegal move has been made, or that pieces have been displaced, the game is restored to the position before the irregularity. If that position cannot be determined, the game is restored to the last known correct position.[74]

An illegal position is a position which cannot be reached by any series of legal moves.[75]

Players may not use any notes, outside sources of information (including computers), or advice from other people. Analysis on another board is not permitted. Scoresheets are to record objective facts about the game only, such as time on the clock or draw offers. Players may not leave the competition area without permission of the arbiter.[76]

High standards of etiquette and ethics are expected. Players should shake hands before and after the game. Generally a player should not speak during the game, except to offer a draw, resign, or to call attention to an irregularity. An announcement of "check" is commonly made in informal games but is not recommended in officially sanctioned games. A player may not distract or annoy another player by any means, including repeatedly offering a draw.[77]

Due to increasing concerns about the use of chess engines and outside communication, mobile phone usage is banned. The first forfeit by a high-profile player, for phone ringing during play, occurred in 2003.[78] In 2014 FIDE extended this to ban all mobile phones from the playing area during chess competitions, under penalty of forfeiture of the game or even expulsion from the tournament. The rules allow for less rigid enforcement in minor events.[79]

FIDE rulebook, 1989

Official Chess Rulebook, by Harkness (1970 edition)

The first known publication of chess rules was in a book by Luis Ramírez de Lucena about 1497, shortly after the movement of the queen, bishop, and pawn were changed to their modern form.[97] Ruy López de Segura gave rules of chess in his 1561 book Libro de la invencion liberal y arte del juego del axedrez.[98] In the 16th and 17th centuries, there were local differences concerning rules such as castling, promotion, stalemate, and en passant. Some of these differences persisted until the 19th century;[99] for example, differences in castling rules persisted in Italy until the late 19th century.

As chess clubs arose and tournaments became common, there was a need to formalize the rules. In 1749 Philidor (1726–1795) wrote a set of rules that were widely used, as well as rules by later writers such as the 1828 rules by Jacob Sarratt (1772–1819) and rules by George Walker (1803–1879). In the 19th century, many major clubs published their own rules, including The Hague in 1803, London in 1807, Paris in 1836, and St. Petersburg in 1854. In 1851 Howard Staunton (1810–1874) called for a "Constituent Assembly for Remodeling the Laws of Chess" and proposals by Tassilo von Heydebrand und der Lasa (1818–1889) were published in 1854. Staunton had published rules in Chess Player's Handbook in 1847, and his new proposals were published in 1860 in Chess Praxis; they were generally accepted in English-speaking countries. German-speaking countries usually used the writings of chess authority Johann Berger (1845–1933) or Handbuch des Schachspiels by Paul Rudolf von Bilguer (1815–1840), first published in 1843.

In 1924, Fédération Internationale des Échecs (FIDE) was formed and in 1928 it took up the task of standardizing the rules. At first FIDE tried to establish a universal set of rules, but translations to various languages differed slightly. Although FIDE rules were used for international competition under their control, some countries continued to use their own rules internally.[100] In 1952, FIDE created the Permanent Commission for the Rules of Chess (also known as the Rules Commission) and published a new edition of the rules. The third official edition of the laws was published in 1966. The first three editions of the rules were published in French, with that as the official version. In 1974 FIDE published the English version of the rules (which was based on an authorized 1955 translation). With that edition, English became the official language of the rules. Another edition was published in 1979. Throughout this time, ambiguities in the laws were handled by frequent interpretations that the Rules Commission published as supplements and amendments. In 1982, the Rules Commission rewrote the laws to incorporate the interpretations and amendments.[101] In 1984, FIDE abandoned the idea of a universal set of laws, although FIDE rules are the standard for high-level play.[102] With the 1984 edition, FIDE implemented a four-year moratorium between changes to the rules. Other editions were issued in 1988 and 1992.[103][104]

The rules of national FIDE affiliates (such as the United States Chess Federation, or USCF) are based on the FIDE rules, with slight variations.[105][106][107] Some other differences are noted above. Kenneth Harkness published popular rulebooks in the United States starting in 1956, and the USCF continues to publish rulebooks for use in tournaments it sanctions.

In 2008, FIDE added the variant Chess960 to the appendix of the "Laws of Chess". Chess960 uses a random initial set-up of main pieces, with the conditions that the king is placed somewhere between the two rooks, and bishops on opposite-color squares. The castling rules are extended to cover all these positions.[108]

In the 21st century, rules about such things as mobile phones and unauthorised use of chess engines were introduced.[79]