Chess

Chess is a board game played between two players. It is played on a chessboard, which is a square-checkered board with 64 squares arranged in an eight-by-eight grid. At the start, each player controls sixteen pieces: one king, one queen, two rooks, two knights, two bishops, and eight pawns. The object of the game is to checkmate the opponent's king, whereby the king is under immediate attack (in "check") and there is no way to remove or defend it from attack on the next move.

The current form of the game emerged in Europe during the second half of the 15th century after evolving from a much older game of Indian origin. Aspects of art are found in chess composition. Theoreticians have developed extensive chess strategies and tactics since the game's inception. One of the goals of early computer scientists was to create a chess-playing machine. Chess is now deeply influenced by the abilities of chess programs and the opportunity for online play. In 1997 Deep Blue became the first computer to beat a reigning World Champion in a match when it defeated Garry Kasparov.

The tradition of organized competitive chess started in the 16th century. The first official World Chess Champion, Wilhelm Steinitz, claimed his title in 1886; the current World Champion is Viswanathan Anand. Chess is a recognized sport of the International Olympic Committee. Today, chess is one of the world's most popular games, played by millions of people worldwide at home, in clubs, online, by correspondence, and in tournaments.

Rules

The official rules of chess are maintained by the World Chess Federation. Along with information on official chess tournaments, the rules are described in the FIDE Handbook, section Laws of Chess.^[1] For a demonstration of the gameplay, see a sample chess game.

Chess is played on a square board of eight rows (called ranks and denoted with numbers 1 to 8) and eight columns (called files and denoted with letters a to h) of squares. The colors of the sixty-four squares alternate and are referred to as "light squares" and "dark squares". The chessboard is placed with a light square at the right hand end of the rank nearest to each player, and the pieces are set out as shown in the diagram, with each queen on its own color.

The pieces are divided, by convention, into white and black sets. The players are referred to as "White" and "Black", and each begins the game with sixteen pieces of the specified color. These consist of one king, one queen, two rooks, two bishops, two knights and eight pawns.

Movement

The players alternate moving one piece at a time (with the exception of castling, when two pieces are moved simultaneously). Pieces are moved to either an unoccupied square, or one occupied by an opponent's piece, capturing it and removing it from play. With the sole exception of en passant, all pieces capture opponent's pieces by moving to the square that the opponent's piece occupies.

White always moves first. Each chess piece has its own style of moving. The Xs mark the squares where the piece can move if no other pieces (including one's own piece) are on the Xs between the piece's initial position and its destination. If there is an opponent's piece at the destination square, then the moving piece can capture the opponent's piece. The only exception is the pawn which can only capture pieces diagonally forward.

Castling

Once in every game, each king is allowed to make a special move, known as castling. Castling consists of moving the king two squares along the first rank toward a rook, then placing the rook immediately on the far side of the king. Castling is only permissible if all of the following conditions hold.

·      Neither of the pieces involved in the castling may have been previously moved during the game;

·      There must be no pieces between the king and the rook;

·      The king and the rook must be on the same rank;

·      The king may not currently be in check, nor may the king pass through squares that are under attack by enemy pieces. As with any move, castling is illegal if it would place the king in check.

En Passant

When a pawn advances two squares, if there is an opponent's pawn on an adjacent file next to its destination square, then the opponent's pawn can capture it and move to the square the pawn passed over, but only on the next move. For example, if the black pawn has just advanced two squares from g7 to g5, then the white pawn on f5 can take it via en passant on g6.

Promotion

When a pawn advances to its eighth rank, it is exchanged at the player's choice for a queen, rook, bishop, or knight of the same color. Usually, the pawn is chosen to be promoted to a queen, but in some cases another piece is chosen, called underpromotion. In the diagram on the right, the pawn on c7 can choose to advance to the eighth rank to promote to a better piece.

Check

When a king is under immediate attack by one or two of the opponent's pieces, it is said to be in check. The only permissible responses to a check are to capture the checking piece, interpose a piece between the checking piece and the king (unless the attacking piece is a knight), or move the king to a square where it is not under attack. Castling is not a permissible response to a check, nor is it permissible during the castle move for the king to travel over a space that is considered to be in check. A move that would place the moving player's king in check is illegal. The object of the game is to checkmate the opponent; this occurs when the opponent's king is in check, and there is no way to remove it from attack.

Stalemate

A stalemate occurs when, for the player with the move:

·      The player has no legal moves, and

·      The player's king is not in check

If this happens, the king is said to have been stalemated and the game ends in a draw. A player who has very little or no chance of winning will often try to entice the opponent to inadvertently place the player's king in stalemate in order to avoid a loss.

End of the game

The objective of the game is to checkmate the opponent. This occurs when a move places the opponent's king in check, and there is no legal response for the opponent that removes it from attack.

History

Predecessors

Chess is commonly believed to have originated in North-West India during the Gupta empire, where its early form in the 6th century was known as caturaṅga (Sanskrit: four divisions [of the military] – infantry, cavalry, elephants, and chariotry, represented by the pieces that would evolve into the modern pawn, knight, bishop, and rook, respectively). The earliest evidence of Chess is found in the neighboring Sassanid Persia around 600 where the game is known under the name became chatrang. Chatrang is evoked inside three epic romances written in Pahlavi (Medium Persian). Chatrang was taken up by the Muslim world after the Islamic conquest of Persia (633–644) where it was then named shatranj, with the pieces largely retaining their Persian names. In Spanish "shatranj" was rendered as ajedrez, in Portuguese as xadrez, and in Greek as zatrikion (which directly comes from Persian chatrang, but in the rest of Europe it was replaced by versions of the Persian shāh ("king"), which was familiar as an exclamation and became our words "check" and "chess". Murray theorized that this change happened from Muslim traders coming to European seaports with ornamental chess kings as curios before they brought the game of chess.The game reached Western Europe and Russia by at least three routes, the earliest being in the 9th century. By the year 1000 it had spread throughout Europe. Introduced into the Iberian Peninsula by the Moors in the 10th century, it was described in a famous 13th-century manuscript covering shatranj, backgammon, and dice named the Libro de los juegos. Another theory contends that chess arose from the game xiangqi (Chinese Chess) or one of its predecessors.

 

 

Origins of the modern game (1000–1850)

Around 1200, rules of shatranj started to be modified in southern Europe, and around 1475, several major changes made the game essentially as it is known today. These modern rules for the basic moves had been adopted in Italy and Spain. Pawns gained the option of advancing two squares on their first move, while bishops and queens acquired their modern abilities. The queen replaced the earlier vizier chess piece towards the end of the 10th century and by the 15th century, had become the most powerful piece; consequently modern chess was referred to as "Queen's Chess" or "Mad Queen Chess". These new rules quickly spread throughout western Europe, with the exception of the rules about stalemate, which were finalized in the early 19th century. To distinguish it from its predecessors, this version of the rules is sometimes referred to as western chess or international chess.

Writings about the theory of how to play chess began to appear in the 15th century. The oldest surviving printed chess book, Repetición de Amores y Arte de Ajedrez (Repetition of Love and the Art of Playing Chess) by Spanish churchman Luis Ramirez de Lucena was published in Salamanca in 1497. Lucena and later masters like Portuguese Pedro Damiano, Italians Giovanni Leonardo Di Bona, Giulio Cesare Polerio and Gioachino Greco or Spanish bishop Ruy López de Segura developed elements of openings and started to analyze simple endgames.

In the 18th century the center of European chess life moved from the Southern European countries to France. The two most important French masters were François-André Danican Philidor, a musician by profession, who discovered the importance of pawns for chess strategy, and later Louis-Charles Mahé de La Bourdonnais who won a famous series of matches with the Irish master Alexander McDonnell in 1834. Centers of chess life in this period were coffee houses in big European cities like Café de la Régence in Paris and Simpson's Divan in London.

As the 19th century progressed, chess organization developed quickly. Many chess clubs, chess books and chess journals appeared. There were correspondence matches between cities; for example the London Chess Club played against the Edinburgh Chess Club in 1824. Chess problems became a regular part of 19th-century newspapers; Bernhard Horwitz, Josef Kling and Samuel Loyd composed some of the most influential problems. In 1843, von der Lasa published his and Bilguer's Handbuch des Schachspiels (Handbook of Chess), the first comprehensive manual of chess theory.

King

In chess, the King (♔, ♚) is the most important piece. The object of the game is to trap the opponent's king so that he would not be able to avoid capture (checkmate). If a player's king is threatened with capture, he is said to be in check, and the player must move so as to remove the threat of capture. If he cannot escape capture on the next move, the king is said to be in checkmate, and the player which owns that king loses the game.

In a conventional game of chess, White starts with the king on the first rank to the right of the queen. Black starts with the king directly across from the white king. In algebraic notation, the white king starts on e1 and the black king on e8.

A king can move one square in any direction (horizontally, vertically, or diagonally). The exceptions to this rule are that it may not move onto a square that is threatened by an enemy piece, or one that is already occupied by another piece on its own side. As a result, the opposing kings may never occupy adjacent squares (see opposition), but the king can give discovered check by unmasking a bishop, rook, or queen. The king is also involved in the special move of castling. As with all pieces except the pawn, it captures by moving onto a square occupied by an enemy piece.

Queen

The queen (♕,♛) is the most powerful piece in the game of chess and can move in any direction. Each player starts the game with one queen, placed in the middle of their first rank next to their king. The white queen starts on a white square, and the black queen on a black square, thus the mnemonic "queen gets her color" or "queen on color". In algebraic notation, the white queen starts on the d1 square and the black queen starts on the d8 square.

In the game shatranj, an ancestor of chess, the queen was a fairly weak piece called a fers or vizier, only able to move or capture one square in a diagonal direction similar to a pawn. The modern queen's move arose in 15th century Europe.

The piece is archaically known as the minister. In Polish it is known as the Hetman – the name of a major historical military-political office. In Russian it keeps its Persian name of ferz (koroleva or Queen is colloquial and is never used by professional chess players).

The queen can be moved any number of unoccupied squares in a straight line vertically, horizontally, or diagonally, thus combining the moves of the rook and bishop. The queen captures by occupying the square on which an enemy piece sits.

Although both players start with one queen each, a player can promote a pawn to any of several types of pieces including a queen when the pawn is moved to the player's furthest rank, which is the opponents first rank. Such a queen created by promotion can be an additional queen or, if the player's queen has been captured, a replacement queen. Such pawn promotion to a queen can be colloquially called queening, which is by far the most common type of piece a pawn is promoted to because of the power of a queen.

Bishop

A bishop (♗,♝) is a piece in the board game of chess. Each player begins the game with two bishops. One starts between the king's knight and the king, the other between the queen's knight and the queen. In algebraic notation the starting squares are c1 and f1 for White's bishops, and c8 and f8 for Black's bishops.

The canonical chessmen are now dated back to Howard Staunton and the Staunton chess set. The piece's deep groove symbolizes a bishop's (or abbot's) mitre. The groove originates from the original form of the piece, an elephant (the groove represented the elephant's tusks). This groove was interpreted differently in different countries as the game moved to Europe; in France, for example, the groove was taken to be a jester's cap, hence in France the bishop is called "fou" (the fool). In some Slavic languages (e.g. Czech/Slovak) the bishop is called "střelec/strelec", which directly translates to English as a "shooter" meaning an archer, while in others it is still known as "elephant" (e. g. Russian slon). In Swedish the bishop is called "löpare", and in Hungarian "futó", both of which directly translates to English as "runner".

The bishop has no restrictions in distance for each move, but is limited to diagonal movement. Bishops, like all other pieces except the Knight, cannot jump over other pieces. A bishop captures by occupying the square on which an enemy piece sits.

The bishops may be differentiated according to which wing they begin on, i.e. the king's bishop and queen's bishop. As a consequence of its diagonal movement, each bishop always remains on either the white or black squares, and so it is also common to refer to them as light-squared or dark-squared bishops.

Knight

The knight (♘ ♞) is a piece in the game of chess, representing a knight (armoured cavalry). It is normally represented by a horse's head, leading some to refer to it informally as a "horse".

Each player starts with two knights, which start on the rank closest to the player. Expressed in algebraic notation, the white knights start on b1 and g1, while the black knights start on b8 and g8.

The knight move is unusual among chess pieces. When it moves, it can move two squares horizontally and one square vertically, or two squares vertically and one square horizontally. The complete move therefore looks like the letter 'L'. Unlike all other standard chess pieces, the knight can 'jump over' all other pawns and pieces (of either color) to its destination square. It captures an enemy piece by moving into its square. The knight's ability to 'jump over' other pieces means it is at its most powerful in closed positions. The move is one of the longest-surviving moves in chess, having remained unchanged since before the seventh century AD. Because of this it also appears in most chess-related national games. The knight moves alternately to white and black squares.

A knight should always be close to where the action is. Pieces are generally more powerful if placed near the center of the board, but this is particularly true for a knight. A knight on the edge of the board attacks only four squares and a knight in the corner only two. Moreover, it takes more moves for a decentralized knight to switch operation to the opposite side of the board than a decentralized bishop, rook, or queen. The mnemonic phrases "A knight on the rim is grim" or "A knight on the rim is dim" are often used in chess instruction and reflect these features.

The knight is the only piece that can move at the beginning of the game before any pawn move has been made. Because of the above reasons, in most situations the best square for the initial move of each knight is one towards the center. Knights are usually brought into play slightly sooner than the bishops and much sooner than the rooks and the queen.

The knight is the only piece that can be in position to attack a king, queen, bishop, or rook without being reciprocally attacked by that piece. The knight is thus especially well-suited for executing a fork.

Rook

A rook (♖ ♜ borrowed from Persian رخ rokh, Sanskrit rath, "chariot") is a piece in the strategy board game of chess. In the past the piece was called the castle, tower, marquess, rector, and comes (Sunnucks 1970), and non-players still often call it a "castle".^] Using the rook in a specialized double-movement with the king is still refered to as castling. Each player starts with two rooks, one in each of the corners nearest their own side.In algebraic notation, the white rooks start on the a1 and h1 squares, while the black rooks start on the a8 and h8 squares. The rook moves horizontally or vertically, forward or back, through any number of unoccupied squares, as shown in the diagram. Like other pieces, it captures by occupying the square on which an enemy piece stands. The rook also participates, along with the king, in a special move called castling.

Pawn

The pawn (♙♟) is the most numerous and (in most circumstances) the weakest piece in the game of chess, representing infantry, or more particularly armed peasants or pikemen. Each player begins the game with eight pawns, one on each square of the second rank from the view of the player. In algebraic notation the white pawns start on a2, b2, c2, ..., h2, while the black pawns start on a7, b7, c7, ..., h7.

Pawns are differentiated by the files on which they currently stand. For example, one speaks of "White's f-pawn" or "Black's b-pawn" or, less commonly, "White's king's bishop's pawn" or "Black's queen's knight's pawn" (using descriptive notation). It is also common to refer to a rook pawn, meaning any pawn on the a-file or h-file, a knight pawn (on the b- or g-file), a bishop pawn (on the c- or f-file), a queen pawn (on the d-file), a king pawn (on the e-file), and a central pawn (on either the d- or e-file).

As pawns differ so much from other pieces, the usage of the word pieces in chess literature usually excludes the pawns, although this distinction between "pieces" and "pawns" is not found in the official rules.

Pawns are unusual in movement and use. Unlike all the other pieces, pawns may not move backwards. Normally a pawn moves by advancing a single square, but the first time each pawn is moved from its initial position, it has the option to advance two squares. Pawns may not use the initial two-square advance to jump over an occupied square, or to capture. Any piece directly in front of a pawn, friend or foe, blocks its advance. In the diagram at right, the pawn on c4 may move to c5, while the pawn on e2 may move to either e3 or e4.