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Rules of chess

The rules of chess, as codified by the , govern a two-player played on an 8×8 checkered comprising 64 alternating light and dark squares, with each player starting with 16 pieces—including one , one , two rooks, two bishops, two knights, and eight pawns—positioned symmetrically on opposite sides of the board, and the primary objective being to the opponent's by placing it under inescapable attack. The game begins with white moving first, and players alternate turns, with each piece having distinct movement capabilities: the king moves one square in any direction; the queen combines the rook's horizontal and vertical range with the bishop's diagonal mobility, allowing unlimited squares in those lines; rooks traverse any number of unoccupied squares horizontally or vertically; bishops slide any distance diagonally on the same color; knights follow an L-shaped path of two squares in one direction and one perpendicular, uniquely jumping over intervening pieces; and pawns advance one square forward (or two from their initial position) but capture diagonally forward, while promoting upon reaching the opponent's back rank to become a queen, rook, bishop, or knight. Special moves enhance strategic depth, including castling, where the king shifts two squares toward an unmoved rook, which then jumps to the king's other side, provided neither has moved previously, no pieces obstruct the path, the king is not in check or passing through attacked squares, and the rook's destination is unoccupied; and en passant, a pawn capture option where a pawn advancing two squares from its start can be taken by an opponent's pawn as if it had moved only one, but only immediately on the next turn. The rules also prohibit moves that leave one's own king in check and mandate touching a piece to move it (the "touch-move" principle), with additional provisions for adjusting pieces or claiming a draw under specific conditions like threefold repetition or the 50-move rule. A game concludes in victory by , where the opponent's faces with no legal escape; , insufficient material, or agreement can result in a , while or time expiration (in timed play) may also end the contest, all under FIDE's basic and competition rules that apply to over-the-board play and have been standardized since their approval by the FIDE in 2022, effective from January 1, 2023.

Setup

Board and squares

The is an essential component of the game, consisting of an 8 by 8 grid that forms 64 equal squares arranged in alternating light and dark colors. The squares are colored such that adjacent squares differ in shade, creating a checkered pattern, with the light squares traditionally designated as "white" and the dark as "black." This alternating coloration aids players in visualizing the board and tracking piece movements. The board is oriented between the two players so that the nearest right-hand corner square for each is light (white). From White's perspective, this places the bottom-left square (a1) as dark and the bottom-right square (h1) as light, ensuring consistency in setup. The standard dimensions for over-the-board play in official competitions specify that each square measures between 5 and 6 cm on each side, allowing the board's playing area to span approximately 40 to 48 cm square, though total board size including borders typically falls within 40 to 60 cm to accommodate tournament standards and tolerances set by the International Chess Federation (). These specifications ensure uniformity and playability across events. To facilitate move recording and analysis, the chessboard employs algebraic notation, a standardized by . The vertical columns, known as files, are labeled a through h from left to right as viewed by , while the horizontal rows, called ranks, are numbered 1 through 8 from bottom to top from White's viewpoint. Each square is thus uniquely identified by combining its file letter and rank number, such as for the central square. This system aligns with the board's orientation rule, positioning White's queenside on the dark square a1. Algebraic notation is the sole officially recognized method for FIDE tournaments, promoting precise and universal communication of positions.

Initial position

The chessboard begins with a specific arrangement of pieces for each player, ensuring a balanced starting position. For White, the pieces are placed on the first and second ranks: the rooks occupy and h1, the knights are on and g1, the bishops stand on c1 and f1, the queen is positioned on d1, and the king is on e1; all eight pawns are aligned on the second rank from to h2. Black's setup mirrors White's but on the opposite side of the board, with pieces on the seventh and eighth ranks: the rooks are on a8 and h8, the knights on b8 and g8, the bishops on c8 and f8, the queen on d8, and the king on e8; the pawns occupy the seventh rank from a7 to h7. This arrangement creates a vertically symmetric initial position across the board's central ranks, where identical positions occurring three times during a game, including repetitions of the starting setup, result in a draw by . No pieces from opposing sides begin in contact or able to capture one another immediately, and all pawns start unprotected by other pieces.

Core Gameplay

Turn order and colors

In chess, the player controlling the pieces always makes the first move of the game, after which the players alternate turns until concludes. The pieces are light-colored, while the pieces are dark-colored, with the oriented such that a white square is nearest the right-hand corner of each player. Colors are assigned to players either by lots before the first or by decision of the organizer, particularly in official competitions governed by . In multi-round tournaments, pairing systems are designed to alternate colors for each player across games, aiming for an equal number of and assignments to promote fairness; this may involve algorithmic adjustments to reverse initial color preferences if imbalances arise. Each turn requires the to make exactly one legal move with one of their pieces, and there is a strict to move—no may or skip their turn. This structure grants a slight initiative advantage, as evidenced by large databases: in the masters database, scores approximately 54% of the points overall, reflecting higher win rates and draw frequencies compared to black.

Basic piece movements

In chess, each of the six types of has a distinct method of , determining its and strategic value on the 8×8 board. generally move to unoccupied squares or capture by replacing an opponent's on the target square, except for pawns which capture differently; no may move to a square occupied by a friendly . Sliding —, , and —require a clear path without intervening of either color. The king moves one square in any direction: horizontally, vertically, or diagonally. It captures by moving to the square occupied by an unprotected opponent's piece, but its limited range makes it vulnerable to attacks that constitute check. The queen is the most versatile piece, able to move any number of squares along a rank, file, or diagonal. It captures by advancing to the square of an opponent's piece in those directions, provided the path is unobstructed. The moves any number of squares horizontally along a or vertically along a . Like other sliding pieces, it captures by replacement on the target's square if the intervening path is empty. The bishop travels any number of squares diagonally in any direction, remaining confined to squares of the same color throughout the game due to the board's alternating pattern. It captures opponent's pieces on its diagonal path, but cannot pass over any pieces en route. The moves in an L-shape: two squares in one direction (horizontal or vertical) followed by one square perpendicular, or , allowing it to reach up to eight possible squares. Uniquely, it can jump over both friendly and enemy pieces without obstruction, and captures by landing on the occupied square. The advances forward one square to an empty square, or two squares from its initial position if both are vacant. It captures by moving diagonally forward one square to an adjacent occupied by an opponent's piece, but cannot advance diagonally otherwise.

Special moves

In chess, several special moves allow for exceptional maneuvers under specific conditions, enhancing strategic depth while adhering to strict rules. These include the initial two-square advance for , for the king and , capture for pawns, and pawn promotion upon reaching the opponent's back . The initial two-square advance permits a pawn, on its first move from the second , to proceed forward two squares along the same , provided both the destination square and the intermediate square are unoccupied. This option supplements the standard one-square forward movement and is only available once per pawn, enabling quicker development in the opening phase. Castling is a unique maneuver involving and one of the same color, executed as a single move along the player's first . transfers two squares toward the , after which the moves to the square immediately on the opposite side of . This special move is permissible only if neither nor the chosen has previously moved; no pieces intervene between them; and is not currently in , does not pass through a square , and does not end on a square . Queenside castling follows the same principles but positions on c1 (for ) or c8 (for ), with the on d1 or d8 respectively. If conditions for one side are unmet, castling on the other side may still be possible, but the right is forfeited entirely once either piece moves. En passant is an exclusive pawn capture that occurs when an opponent's advances two squares from its starting position, landing adjacent to the capturing on the same . In this scenario, the opponent's is treated as if it had advanced only one square, allowing the adjacent to capture it by moving to the square the advanced passed over. This capture must be executed immediately on the next move following the two-square advance; otherwise, the opportunity is lost forever. The captured is removed from the board as in a standard capture. Pawn promotion transpires when a pawn reaches the furthest distant rank from its starting position— the eighth rank for or the first for . At that point, the pawn is immediately replaced by a , , , or of the same color, with the choice made by the irrespective of prior captures or the number of pieces already on the board. This exchange occurs as part of the same move that advances the pawn to the promotion square, and the new piece takes effect instantly for any subsequent captures or checks. While to a is most common, underpromotion to other pieces can occur in tactical situations, such as avoiding .

Check

In chess, a king is said to be in check when it is under direct attack by one or more of the opponent's pieces, meaning the opponent could capture the on their next turn if the position were not addressed. This attack is determined by the standard movement rules of the pieces involved, even if the attacking piece is unable to actually move to the 's square due to constraints such as placing its own in . The player whose is in must respond immediately on their next turn by resolving the threat; failure to do so results in an illegal move. To escape check, the player has three primary options: moving the king to a safe square not under attack by any opponent ; capturing the attacking piece with another (including the king, if adjacent and unprotected); or interposing another between the king and the attacker, which is only possible for ranged pieces like , rooks, or bishops that attack along lines. Knights, being non-ranged, cannot be blocked against. These responses must result in a legal position where the king is no longer attacked. A fundamental prohibition in chess is that no move may place or leave one's own in , including moving into a square under attack or exposing the by moving a protecting piece away. This rule extends to pinned pieces: if a piece is pinned to its by an opponent's attack (meaning its movement would expose the to ), it cannot move unless doing so captures the pinning piece or otherwise resolves the threat without leaving the in . One common way check arises is through a discovered check, where a player moves a piece away from its position, thereby uncovering an attack on the opponent's from another piece that was previously blocked by the moving piece. This move simultaneously achieves the discovery and the check, forcing the opponent to respond as usual.

Game Conclusion

Checkmate

Checkmate is the decisive winning condition in chess, occurring when a player's is placed in check and there is no legal move available to escape the threat. This means the king cannot move to a safe square, capture the attacking piece, or have another piece interpose to block the check. According to the official rules, the king is in check if it is attacked by one or more of the opponent's pieces, even if that piece is unable to move to the king due to other constraints. Upon delivering with a legal move, the game ends immediately, and the player who checkmated the opponent's is declared the winner. No further moves are made, and the result is recorded as a win for the victor. This contrasts with ongoing play in , where the player must respond to remove the threat on their next turn. It is important to distinguish from , which occurs when the player whose turn it is to move has no legal moves available but their is not in ; in such cases, the game is immediately drawn rather than lost. prevents a win even if the position appears advantageous for the opponent, emphasizing the rules' balance between attack and defense.

Draws

In chess, a draw occurs when the game ends without a winner, typically due to specific conditions that prevent either player from achieving checkmate. This contrasts with checkmate, where one player forces the opponent's king into an inescapable check, resulting in victory. Draws ensure fair play in positions where continued competition cannot lead to a decisive outcome. Stalemate is a draw declared when the player whose turn it is to move has no legal moves available and their king is not in check. This rule, outlined in Article 5.2.1 of the FIDE Laws of Chess, protects the player from an automatic loss in a non-threatening position, promoting strategic depth by discouraging overly aggressive play that leaves the opponent with no options. For example, if a king is cornered by enemy pieces but not attacked, and all other pieces are immobilized, the game ends in stalemate. A dead position results in a draw when neither player can possibly the opponent's through any sequence of legal moves, as specified in Article 5.2.2. This encompasses scenarios with insufficient , such as versus , and versus , or and versus , where is theoretically impossible regardless of skill. The arbiter or players may claim this immediately upon recognition, ensuring the game does not prolong unnecessarily in hopeless endgames. The threefold repetition rule draws the game if the same position occurs , with the same to move and the same possible moves available for each , per 9.2. Positions are considered identical based on board setup, castling rights, possibilities, and whose turn it is; a can claim this by writing their move, stopping the clock, and notifying the arbiter. This prevents endless repetition tactics and maintains game momentum. Additionally, if the position repeats five times without a claim, the game is automatically drawn under 9.6.1. Under the (Article 9.3), the game is drawn if fifty consecutive moves have been made by each player without any capture or move. This claim follows the same procedure as : writing the move and alerting the arbiter. The rule counters drawn-out endgames lacking progress, such as rook endgames with blocked pawns. An automatic draw occurs after seventy-five such moves under Article 9.6.2, eliminating the need for claims in prolonged inaction. Players may agree to a at any point after each has made at least one move, as per Article 5.1.2, provided rules permit it. The offer must be made after a player's move and before pressing the clock (Article 9.1), recorded with an (=) on the scoresheet, and cannot be retracted until the opponent responds. This mutual consent allows termination in balanced or fatiguing positions, though some events restrict early agreements to encourage competitive play.

Resignation and other endings

In chess, a may resign at any time after the first move by clearly indicating their intention to concede defeat, resulting in an immediate win for the opponent unless the position is such that the opponent cannot achieve by any possible series of legal moves, in which case the game is drawn. This voluntary termination is common when a recognizes an inevitable loss, such as after significant material disadvantage or a trapped , and it ends the game without further play. A game can also conclude by time forfeit if a player fails to complete the prescribed number of moves within their allotted time under the applicable , leading to a loss for that player unless the position prevents the opponent from checkmating, resulting in a . Time controls, which dictate the duration for making moves, are standard in competitive play and enforced via a . Disqualification occurs when a player persistently refuses to comply with the Laws of Chess, penalized by loss of the game, with the arbiter determining the opponent's score, or through more severe measures such as fines, exclusion from a round, or expulsion from the competition. Such penalties address serious violations, ensuring fair conduct in tournaments. In modern tournaments, abandoned games—where play is interrupted and cannot resume promptly—are rare due to the prevalence of time controls that require completion on-site, but if a game must be adjourned, the player in turn seals their move in an for later resumption, with failure to arrive on time (typically after one hour) resulting in loss. Adjudication by a to decide unfinished games, once common in the past, is now virtually obsolete in -regulated events.

Standard Procedures

Touch-move rule

The , also known as the "touch and move" principle, mandates that a player who deliberately touches a on the board must legally move or capture with it if possible, thereby preventing hesitation or retraction after physical contact. This rule applies during a player's turn and ensures by committing players to their initial intentions. Under the , if a player touches one or more of their own with the of moving, they must move the first touched that has a legal move available. Similarly, touching one or more of the opponent's requires capturing the first opponent's touched that can be legally captured. In cases where both own and opponent's are touched, the player must first attempt to capture the opponent's with their own touched if legal; otherwise, they must move or capture the first possible touched. Accidental touches without to move do not trigger the obligation, but intent is presumed unless clearly otherwise. An exception exists for adjusting pieces: only the player whose turn it is may reposition one or more pieces on their squares, but they must first verbally announce their intention, such as by saying "j'adoube" ( for "I adjust") or "I adjust," before touching them. Failure to do so invokes the . The rule extends to special moves like and . For , if a touches their and then a (or simultaneously), they must castle on that side if legally possible; touching the first prohibits castling with that on that turn and requires moving the if possible. In , the choice of the promoted piece is finalized once the new piece touches the promotion square, and the pawn does not need to be physically placed there first. In competitive play governed by organizations like or USCF, non-compliance constitutes an illegal move, typically resulting in the arbiter enforcing the correct move, adding two minutes to the opponent's clock for the , and potentially declaring the game lost for repeated violations. In casual play, the is a customary observed among players by mutual agreement, but formal penalties are generally not imposed, relying instead on good sportsmanship to resolve disputes.

Notation and move recording

In chess, the standard method for recording moves is algebraic notation, which FIDE recognizes as the only permissible system for its tournaments and matches. This notation uses letters to denote pieces and coordinates to specify squares on the 8x8 board, where files are labeled a through h from left to right for White (and right to left for Black), and ranks are numbered 1 through 8 from bottom to top for White (and top to bottom for Black). Standard Algebraic Notation (SAN) describes moves by indicating the piece moved (if not a pawn), the destination square, and any necessary disambiguation to clarify identical moves by multiple pieces. Pieces are abbreviated as K for king, Q for queen, R for rook, B for bishop, and N for knight, while pawns are denoted solely by their destination square. For example, a knight moving to f3 is recorded as Nf3; a capture is marked with an 'x', such as Bxe5 for a bishop capturing on e5; check is indicated by +, and checkmate by #. If ambiguity arises, the originating file (e.g., Nbd2 to distinguish which knight on b-file moves to d2) or rank is added, or both if needed (e.g., Nbc1d3). Special moves include castling as 0-0 (kingside) or 0-0-0 (queenside), and en passant as e.p. Players may use the first letter of piece names in their national language (e.g., 'F' for bishop in French), but the algebraic structure remains mandatory. During a game, players are required to record both their own moves and their opponent's on an official scoresheet, writing legibly in algebraic notation after each move, as clearly as possible, unless they have less than five minutes remaining without a 30-second increment or more, in which case recording is optional (Article 8.4). The scoresheet must remain visible to the arbiter at all times, and players may not write moves in advance except in specific cases like draw claims. At the game's conclusion, both players sign the scoresheet to confirm the result. In tournaments governed by rules, this recording obligation is compulsory; failure to comply can result in penalties imposed by the arbiter, such as warnings, time adjustments, or even loss of the game, depending on the infraction's severity.

Tournament Regulations

Time controls

Time controls in chess regulate the duration of games through the use of a , ensuring fair play and timely conclusions in competitive settings. A consists of two time displays connected such that only one runs at a time, with each display featuring a flag that indicates the expiration of a player's allotted time upon "flag fall." These clocks can be mechanical (analog), which use hands and a physically falling flag, or electronic (digital), which display time numerically and support advanced features like increments; digital clocks are mandatory for FIDE World Championships, Olympiads, and other top-tier events, with endorsed models including the DGT 3000 and LEAP KK 9908. The standard procedure requires that after completing a move, a player immediately stops their own clock and starts the opponent's, with any time elapsed between the move and clock press counting against their allotment. The arbiter starts clock at the official game commencement time, and the clocks alternate in this manner throughout the game. In cases of irregularity, such as a player failing to press the clock, the opponent may claim the time as part of their own allotment. FIDE categorizes time controls into classical, rapidplay, and blitz based on the total thinking time per player. Classical controls, used in long-format tournaments, provide substantial time for deliberation, such as 90 minutes for the first 40 moves followed by 30 minutes for the remainder in many events, or 100 minutes for 40 moves plus 50 minutes for the next 20 and 15 minutes thereafter in World Championships, often incorporating increments. Rapidplay allows all moves in 10 to 60 minutes per player, or the equivalent with increments up to 60 times the increment value falling in that range. Blitz restricts play to 10 minutes or less per player, or equivalent with smaller increments, promoting fast decision-making. To mitigate rushed endgames, many controls include an increment or delay mechanism. An increment adds a fixed amount of time (typically 2 to 30 seconds) to a player's clock after each move, cumulatively extending the total time as the game progresses. A delay, in contrast, provides a brief pause (e.g., 5 to 10 seconds) before the main countdown begins after pressing the clock, preventing immediate time pressure on short moves without adding cumulative time. These features are standard in digital clocks approved by . Flag fall occurs when a player's time expires, observed by the arbiter or claimed by the opponent, triggering an immediate check of whether the player has met the requirements, such as completing a specified number of moves. A player who exceeds their allotted time without fulfilling these requirements forfeits the game on time, unless the position is theoretically drawn (e.g., insufficient material for ), in which case the game is drawn. The default forfeit time is zero minutes, though tournament rules may adjust this. In scenarios where both flags fall simultaneously or indeterminably, the dual-flag rule applies: if the game is not in its final time period, play continues; otherwise, the game is drawn. This rule ensures equity when clock malfunctions or disputes arise regarding the exact timing of flag falls.

Piece handling and irregularities

In chess tournaments governed by FIDE rules, an illegal move—defined as any move that violates the legal movement requirements of the pieces or other fundamental rules, such as failing to meet the conditions for or —must be corrected immediately upon discovery by the arbiter or opponent. According to Article 7.5.1 of the FIDE Laws of Chess, if an illegal move has been made, the position immediately before that move shall be reinstated, and the player must make a legal move instead. In standard time controls, the first illegal move incurs a time penalty of two minutes added to the opponent's clock; in and , it is one minute. A second illegal move results in loss of the game in all formats, unless the opponent has no possible way to . If an incorrect setup of the pieces is discovered before the first move of the game, the entire game is annulled under 7.2.1, and a new game begins with the board correctly arranged, ensuring fairness from the outset. During the game, if a misplacement of pieces is found that creates an illegal position (one unreachable by legal moves), 7.6 requires reinstatement of the position prior to the irregularity if possible, or continuation from the corrected setup determined by the arbiter using their best judgment. Such adjustments may involve pausing the clocks and consulting scoresheets to reconstruct the board accurately, with potential penalties applied to the player responsible for the error. Piece displacement, such as accidentally knocking over one or more pieces during play, falls under Article 7.4, where the player who caused the displacement must restore the pieces to their correct positions using their own time. If restoration is not immediately possible, the arbiter may intervene by pausing the game clock under Article 7.4.2 to assist, and Article 7.4.3 allows the arbiter to impose penalties, ranging from warnings to time additions or even forfeiture in severe or repeated cases. This rule promotes careful handling of equipment while minimizing disruptions to the game's flow. Touching the wrong piece mid-game invokes the outlined in Article 4.3, requiring the to move or capture with the touched if legally possible, as a safeguard against tactical advantages from accidental contact. For instance, if a touches an opponent's , they must capture it if a legal capture exists; failure to do so upon reminder constitutes an irregularity subject to correction. This principle, briefly referenced in the , extends to all interactions to maintain the integrity of moves.

Player conduct

In competitive chess, players are expected to maintain silence and avoid any actions that could distract or annoy their opponents, such as unnecessary talking, excessive movement, or unreasonable offers during the game. This fosters a focused playing environment where opponents can concentrate without interference. Electronic devices, including mobile phones, are strictly prohibited in the playing venue unless approved by the arbiter, and their unauthorized use results in an immediate loss of the game. Fair play is a cornerstone of chess conduct, requiring players to refrain from analyzing the game on another board, consulting notes or external sources of information, or seeking advice from spectators or others during play. Players must also assist arbiters in reconstructing games if necessary and adhere to all tournament rules without attempting to gain unfair advantages. Violations of these principles, including any behavior that brings the game into disrepute, are treated as serious infractions. Penalties for breaches of player conduct are determined by the arbiter and can escalate based on severity and persistence, including verbal warnings, adjustments to time controls (such as adding time to the opponent or deducting from the offender), point deductions, declaration of the game as lost, fines, exclusion from the tournament, or even expulsion from the playing venue. For instance, persistent refusal to comply with conduct rules leads to forfeiture of the game, while allegations may result in broader sanctions like bans from future events under FIDE's regulations. In FIDE-sanctioned events, players must adhere to a formal known as "smart business attire" to uphold the professionalism of the competition, applicable to all participants including officials and arbiters. For men, acceptable attire includes suits, trousers, long- or short-sleeve shirts, polo shirts, jackets, vests, sweaters, and appropriate footwear like shoes or loafers, with national traditional dress permitted upon approval by the Technical Delegate. Women may wear suits, dresses, skirts, blouses, turtlenecks, shirts, polos, trousers, jackets, vests, sweaters, scarves, and footwear such as boots, flats, or mid- to high-heel shoes, also allowing approved national costumes. Prohibited items include , (except in updated guidelines permitting non-distressed dark jeans), T-shirts (unless formal for women), and any torn or casual clothing like beachwear or shorts. Non-compliance incurs fines—€200 for open events and €100 for women's events on the first offense, allowing participation in the current round—escalating to exclusion from subsequent rounds for repeat violations, enforced by the Chief Arbiter and Athletes Commission. further emphasizes respect, such as shaking hands before and after games, though this is more a customary norm than a codified rule in laws.

Adjudication and disputes

In chess tournaments governed by , the arbiter plays a central role in resolving disputes by ensuring the Laws of Chess are observed and intervening only in specified cases, such as irregularities in play, claims of , or violations that affect . According to Article 12.6 of the FIDE Laws of Chess, the arbiter must not intervene except as described in the laws, and they are prohibited from indicating the number of moves completed unless necessary for a claim or other procedural matters. For instance, if an irregularity like an illegal move is observed, the arbiter restores the correct position and adjusts the clock if applicable, under Article 7.1. Players may claim draws by (Article 9.2) or the (Article 9.3), requiring them to write the move, notify the opponent, and alert the arbiter, who then pauses the clock to verify the claim. If the claim is correct, the game is declared a draw; if incorrect, the claimant receives a two-minute penalty added to the opponent's clock (Article 9.5). These verifications ensure objective resolution, preventing disputes over position history. Adjournment, once common in long games without time controls, is now rare in over-the-board tournaments due to standardized time limits but remains possible in specific events like certain national championships. Under Guidelines I, if a game cannot finish within the playing session, the player to move seals their move in an overseen by the arbiter, and the game resumes later without analysis of the sealed position being permitted. Ambiguous or illegal sealed moves result in a loss for the sealing player (Guideline I.8). For unresolved disputes, players risk forfeit, scoring zero points while the opponent receives one (Article 10.1), particularly if they fail to appear or comply with arbiter rulings. Appeals against arbiter decisions can be lodged by players or team captains within one hour for standardplay or fifteen minutes for / after the Chief Arbiter's ruling (Article 3.4 of Appeals Procedural Rules). The appeal, submitted in English with a refundable , is reviewed by an Appeals comprising a titled player and an International Arbiter from different federations, who issue a written decision (Articles 2.1, 3.9). This process upholds fairness in FIDE-sanctioned events, with reports submitted post-tournament (Article 3.12).

Equipment Requirements

Board and pieces

The chessboard used in official games consists of an 8x8 grid of alternating light and dark squares, with each square measuring between 5 and 6 on each side, allowing four pawns to fit comfortably on one square. It is constructed from rigid materials such as wood—typically for light squares and for dark ones—or suitable imitations, with a dull or neutral finish to avoid shine. Colors must contrast clearly, such as white or cream against brown or very light tan, ensuring visibility under standard tournament lighting. Chess pieces follow the Staunton design, named after the 19th-century English chess manufacturer Nathaniel Cook, and are made from wood, plastic, or comparable materials that are non-shiny and aesthetically balanced. The standard heights are approximately 9.5 cm for the king, 8.5 cm for , 7 cm for , 6 cm for , 5.5 cm for , and 5 cm for , with a tolerance of ±10% while preserving the descending order of heights. Base diameters range from 40% to 50% of each piece's height, providing stability; pieces must be distinctly shaped for easy identification, with no two bishops identical and the king's top differing from the queen's coronet. Sets distinguish the two sides through contrasting colors: light pieces in white, cream, or pale shades, and dark pieces in black, brown, or natural wood tones. For international play under auspices, all equipment must be FIDE-compliant, with manufacturers able to obtain official endorsement for use in elite events like the cycle. In some advanced tournaments, FIDE-approved electronic boards may transmit moves digitally while adhering to these physical standards. FIDE continues to update standards for electronic equipment, including partnerships extended through 2028 for digital clocks and boards. Visually impaired players are permitted special tactile sets, featuring Staunton-style pieces with pegs that fit into securing apertures on boards with raised black squares (minimum board size 20 x 20 cm) and marked dark pieces for differentiation by touch. These adaptations ensure accessibility while maintaining core gameplay integrity.

Clocks and scoresheets

In chess tournaments governed by FIDE, a chess clock consists of two interconnected time displays, allowing only one to run at a time, with each display featuring a flag or equivalent indicator to signal the expiration of a player's allotted time, known as flag-fall. FIDE-approved models include both mechanical clocks, which must have a visible, non-reflective flag that falls precisely at full hours and operate silently, and digital clocks, which display time in seconds (preferably), are legible from at least three meters away, include move counters, and support features like low-battery warnings and arbiter adjustments without data manipulation. Examples of endorsed digital models as of 2025 include the DGT 3000 and the more recent DGT 2500. The clock is set by the arbiter to allocate equal time to both players at the start of the game, with White's display activated first. Players must handle the clock by stopping their own display and starting the opponent's with the same hand immediately after making a move; failure to do so properly may result in penalties, such as warnings or loss of the game in severe cases, as determined by the arbiter. If a observes their opponent's fall or suspects stalling (such as not pressing the clock), they may claim the time expiration, prompting arbiter intervention to verify and potentially end the game in the claimant's favor, unless legal requirements for prevent it. In the playing venue, clocks may be broadcast on screens for transparency, and assistants are permitted for players with disabilities to manage the device. Scoresheets are provided by tournament organizers and must be used to record moves in algebraic notation, along with draw offers, clock times, and claims, ensuring legibility and visibility to the arbiter throughout the game. At the game's conclusion, both players sign the scoresheets (or approve electronic versions) to confirm the result, which becomes the official record unless disputed. Electronic scoresheets, such as FIDE-approved systems like Clono (approved in 2022), are permitted in official tournaments as alternatives to paper, provided they comply with recording requirements and prevent unauthorized access. Scoresheets remain the property of the organizers and must be submitted post-game. For accessibility, visually impaired players may use scoresheets, tape recorders, or assistants for recording, while special clocks feature reinforced hands and tactile flags; large-print scoresheets and adapted clocks are also available to accommodate other impairments.

Historical Evolution

Pre-modern rules

The game of chess traces its origins to the ancient Indian chaturanga, which emerged around the CE and was played on an uncheckered board known as the ashtapada. In chaturanga, the pieces represented elements of a fourfold —infantry (pawns), (knights), elephants (precursors to bishops), chariots (rooks), the king, and a counselor (early )—with pawns advancing only one square forward and capturing diagonally, while other pieces had limited mobility, such as the counselor's single diagonal step. The game spread to Persia by the as chatrang, then to the as shatranj after the 7th century conquests, reaching via and by the 10th-12th centuries, where it retained these core mechanics but adapted to local cultures without initial standardization. Early medieval rules featured irregular pawn movements, with no option for an initial two-square advance, and the complete absence of , leaving kings vulnerable to single-square moves only. capture did not exist until the in , coinciding with the pawn's double-step introduction to counterbalance the game's accelerating pace; prior to this, pawns captured only on adjacent files without special provisions for passing moves. Stalemate outcomes varied regionally: in early and some medieval European traditions, it counted as a win for the stalemating player, while in Muslim and parts of , it was a loss, reflecting differing views on whether immobilization constituted defeat or . These inconsistencies highlighted the game's fluid pre-modern state, where local customs often prevailed over uniform rules. During the 15th to 18th centuries in , significant enhancements transformed chess dynamics, most notably the empowerment of —from a weak advisor limited to one diagonal square to a piece capable of unrestricted orthogonal and diagonal movement, a shift documented in and treatises by 1497. Bishops similarly gained full diagonal range, evolving from the elephant's two-square leap in and . emerged as a protective maneuver with variants: in 16th-century , the king could leap over pieces to a third-rank square, while early French and English versions required two separate moves for king and rook, differing from the later single-turn consolidation. National variants further diversified pre-modern chess, such as in 12th- to 19th-century , played on a 12x8 board with additional "courier" pieces that moved like modern bishops but were placed between pawns, alongside enhanced rules for other pieces to fill the expanded space. Other regional adaptations, like the four-player in with dice elements or Timur's great chess on a 10x11 board in the , incorporated unique piece promotions and board geometries, underscoring chess's adaptability before broader codification.

FIDE codification and updates

The Fédération Internationale des Échecs (), founded on 20 July 1924 in , established as one of its primary objectives the unification of chess rules across international competitions to standardize play and resolve discrepancies among national federations. The first official edition of the FIDE Laws of Chess was published in 1929 in , providing a comprehensive codification of the game's basic mechanics, including piece movements, , , and , along with competition guidelines. This initial version aimed to create a universal framework, drawing from prevailing European practices while addressing variations in areas like and . An updated edition followed in 1952, incorporating amendments approved by the FIDE General Assembly and establishing the Permanent Commission for the Rules of Chess to oversee ongoing standardization and interpretation. The 1952 revision expanded on tournament procedures and player obligations, reflecting feedback from post-World War II international events. A third edition appeared in 1966, adding explanatory comments to clarify ambiguities in the rules and promote consistent arbitration. In 1974, the Permanent Commission published the first English-language version of the Laws, based on the French text but adapted for broader global accessibility, which included refinements to draw claims and irregular moves. This marked a shift toward multilingual dissemination, with English becoming the authentic reference by later editions. Subsequent revisions have occurred periodically, typically every four to six years, through proposals reviewed by the Rules Commission and approved at FIDE Congresses, ensuring the Laws adapt to evolving competitive needs without altering core gameplay. Notable updates include the 1982 edition, which introduced penalties for illegal moves and formalized rapidplay rules; the 1989 version, clarifying electronic clock usage and j'adoube procedures; and the 1997 revision, addressing digital scoresheets and anti-cheating measures. Further significant changes came in 2001 (emphasizing one-handed play and clock handling), 2005 (introducing a four-year moratorium on major alterations), 2009 (refining blitz and rapid distinctions), 2014 (updating draw-by-repetition claims), 2018 (adding provisions for online play elements in over-the-board contexts), and the current 2023 edition, approved at the 93rd Congress in , , which includes clarifications on disconnection in hybrid events and enhanced arbiter guidelines for disputes. These updates prioritize clarity, fairness, and technological integration while preserving the game's integrity, with the English text serving as the authoritative version since 1974.

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