CHESS

Chess is a board game played between two players. The current form of the game emerged in Southern Europe during the second half of the 15th century after evolving from a similar, much older game of Indian origin. 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.

The game 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 (one controlling the white pieces, the other controlling the black pieces) 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 it from attack on the next move.

The tradition of organized competitive chess started in the 16th century. Chess today is a recognized sport of the International Olympic Committee. The first official World Chess Champion, Wilhelm Steinitz, claimed his title in 1886; the current World Champion is Viswanathan Anand. Theoreticians have developed extensive chess strategies and tactics since the game's inception. Aspects of art are found in chess composition.

One of the goals of early computer scientists was to create a chess-playing machine. Today's chess is deeply influenced by the abilities of chess programs and the opportunity for online play. In 1997 Deep Blue became the first computer to beat the reigning World Champion in a match when it defeated Garry Kasparov.

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.For a demonstration of the gameplay, see a sample chess game.

Setup

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.

White always moves first. 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.

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.

Moves

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.

Special moves

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 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 for the player's choice of 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.

End of the game
Chess games do not have to end in checkmate — either player may resign if the situation looks hopeless. If it is a timed game a player may run out of time and lose, even with a much superior position. Games also may end in a draw (tie). A draw can occur in several situations, including draw by agreement, stalemate, threefold repetition of a position, the fifty-move rule, or a draw by impossibility of checkmate (usually because of insufficient material to checkmate).

Time Control
Besides casual games without exact timing, chess is also played with a time control, mostly by club and professional players. If a player's time runs out before the game is completed, the game is automatically lost (provided his opponent has enough pieces left to deliver checkmate). The timing ranges from long games played up to seven hours to shorter rapid chess games lasting usually 30 minutes or one hour per game. Even shorter is blitz chess with a time control of three to fifteen minutes for each player, or bullet chess (under three minutes). Timing is most often controlled using a game clock.
History

Chess is commonly believed to have originated in 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). In Sassanid Persia around 600 the name became shatranj and the rules were developed further. Shatranj was taken up by the Muslim world after the Islamic conquest of Persia (633–644), with the pieces largely retaining their Persian names. In Spanish "shatranj" was rendered as ajedrez, in Portuguese as xadrez, and in Greek as zatrikion, 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 chessor 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.[23] 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.
François-André Danican Philidor, 18th-century French chess Master

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.[28] 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.[29][30]

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.[31] 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.