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Chess

2007 Schools Wikipedia Selection. Related subjects: Games

   Chess
   From left, a white king, black rook and queen, white pawn, black
   knight, and white bishop in a set of Staunton chess pieces.
   Players 2
   Setup time under one minute
   Playing time 10–60 minutes, tournament games last up to 7 hours*
   Rules complexity Medium
   Strategy depth High
   Random chance None
   Skills required Tactics, Strategy
   * Games by correspondence may last many months, while "blitz chess"
   games are even shorter than 10 minutes

   Chess is an abstract strategy board game and mental sport for two
   players. The object of the game is to checkmate the opponent's king.
   This occurs when the king is under immediate attack (in check) and
   there is no way to remove it from attack on the next move.

   Chess is one of the world's most popular board games; it is played both
   recreationally and competitively in clubs, tournaments, online, and by
   mail or e-mail ( correspondence chess).

   Many variants and relatives of chess are played throughout the world.
   The most popular are xiangqi in China and shogi in Japan. Other
   national chess variants include janggi in Korea and makruk in Thailand.
   The game described in this article is sometimes known as Western Chess
   or International Chess to distinguish it from other variants.

Gameplay

Overview


   Image:chess_zhor_26.png
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                           a8 b8 c8 d8 e8 f8 g8 h8
                           a7 b7 c7 d7 e7 f7 g7 h7
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                           a5 b5 c5 d5 e5 f5 g5 h5
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                           a3 b3 c3 d3 e3 f3 g3 h3
                           a2 b2 c2 d2 e2 f2 g2 h2
                           a1 b1 c1 d1 e1 f1 g1 h1
                                                  Image:chess_zver_26.png
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   The position of the pieces at the start of a game of chess.
   A typical Staunton-design chess set and clock.
   Enlarge
   A typical Staunton-design chess set and clock.
    Name  Letter    Picture
   Pawn   P      Pawn Pawn
   Knight N      Knight Knight
   Bishop B      Bishop Bishop
   Rook   R      Rook Rook
   Queen  Q      Queen Queen
   King   K      King King

   Chess is played on a square board of eight rows (called ranks) and
   eight columns (called files) of squares. The colors of the sixty-four
   squares alternate between light and dark, and are referred to as "light
   squares" and "dark squares".

   Each player begins the game with sixteen pieces which can move in
   defined directions, and in some instances, limited range, and can
   remove (capture) other pieces from the board: each player's pieces
   comprise eight pawns, two knights, two bishops, two rooks, one queen
   and one king. One player controls the white pieces and the other player
   controls the black pieces; the player that controls white is always the
   first player to move. The players alternate moving one piece at a time
   (with one important exception) to either an unoccupied square, or one
   occupied by an opponent's piece, capturing it. With one exception ( en
   passant), all pieces capture opponent's pieces by moving to the square
   that the opponent's piece occupies.

   When a king is under direct attack by one (or possibly two) of the
   opponent's pieces, the player is said to be in check. When in check,
   only moves that remove the king from attack are permitted. The object
   of the game is to checkmate the opponent; this occurs when the
   opponent's king is in check, and there are no moves that remove the
   king from attack. Normally a checkmate will require the cooperation of
   several pieces, but can also be achieved with only one, if the king is
   blocked by other pieces (e.g. a back rank checkmate). A player who
   deems checkmate is inevitable may concede the game (resign) to the
   other player. A drawn result (a tie) is also possible.

   Chess has been described not only as a game but also as an art, a
   science, and a sport. It is sometimes seen as an abstract war game; as
   a "mental martial art", and teaching chess has been advocated as a way
   of enhancing mental prowess.

Rules

   When a game begins, one player controls the sixteen white pieces while
   the other uses the sixteen black pieces. The colors are chosen either
   by a friendly agreement, by a game of chance such as pick-a-hand, or by
   a tournament director. The first player, referred to as White, always
   moves first and therefore has a slight advantage over the second
   player, referred to as Black. The chessboard is placed so that each
   player has a white square in the near right hand corner, and the pieces
   are set out as shown in the diagram, with each queen on a square that
   matches its colour.

   Each kind of chess piece moves a different way.
     * The rook moves any number of vacant spaces vertically or
       horizontally;
     * The bishop moves any number of vacant spaces in any direction
       diagonally;
     * The queen is a combination of the rook and bishop - it can move any
       number of spaces diagonally, horizontally, or vertically;
     * The knight can jump over occupied squares and moves two spaces
       horizontally and one space vertically (or vice versa), making an L
       shape; a knight in the middle of the board has eight squares to
       which it can move. Note that every time a knight moves, it changes
       square colour.
     * The king can move only one square horizontally, vertically, or
       diagonally except when a player castles. The player can not make
       any move that would place his king in check;
     * Pawns have the most difficult movement:

          + A pawn can move forward one square, if that square is
            unoccupied. If it has not moved yet, the pawn has the option
            of moving two squares forward, if both squares in front of the
            pawn are unoccupied. A pawn cannot move backward.
          + When such an initial two square advance is made that puts that
            pawn horizontally adjacent to an opponent's pawn, the
            opponent's pawn can capture that pawn " en passant" as if it
            moved forward only one square rather than two, but only on the
            immediately subsequent move.
          + Pawns are the only pieces that capture differently than they
            move. They can capture an enemy piece on either of the two
            spaces adjacent to the space in front of them (i.e., the two
            squares diagonally in front of them), but cannot move to these
            spaces if they are vacant.
          + If a pawn advances all the way to its eighth rank, it is then
            promoted (converted) to a queen, rook, bishop, or knight of
            the same colour. In practice, the pawn is almost always
            promoted to a queen.

   With the exception of the knight, pieces cannot jump over each other.
   One's own pieces ("friendly pieces") cannot be passed if they are in
   the line of movement, and a friendly piece can never replace another
   friendly piece. Enemy pieces cannot be passed, but they can be
   "captured". When a piece is captured (or taken), the attacking piece
   replaces the enemy piece on its square ( en passant being the only
   exception). The king cannot be captured, only put in check. If a player
   is unable to get the king out of check, checkmate results, with the
   loss of the game.

   Chess games do not have to end in checkmate — either player may resign
   if the situation looks hopeless. 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). Chess games and positions are recorded using a
   chess notation, mostly the algebraic chess notation. The international
   rules of chess are described in more detail in the FIDE Handbook,
   section Laws of Chess.

Strategy and tactics

   Chess openings are a sequence of moves, often memorized, which will
   help a player build up his position and prepare for the middlegame.
   Openings are often designed to take hold of the centre of the board
   (e4, e5, d4 and d5), develop pieces, protect the king, and create a
   strong pawn structure. The classical school of chess expounds the
   virtues of occupying the centre early using pawns and/or pieces, while
   Hypermodernism advocates the control of the centre not by using pawns
   but with distant pieces. It is often important for a player to castle
   (a special move that moves the king from the centre of the board two
   squares towards one of the corners) to protect the king. While studying
   openings can greatly improve one's results, it is important to
   understand the underlying reasons for each sequence of moves in an
   opening. This can greatly reduce the need to rely on rote memorization
   of the opening phase of the game. Of the utmost importance in the
   opening is maintaining balance, or equality.

   Image:chess_zhor_26.png
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                           a8 b8 c8 d8 e8 f8 g8 h8
                           a7 b7 c7 d7 e7 f7 g7 h7
                           a6 b6 c6 d6 e6 f6 g6 h6
                           a5 b5 c5 d5 e5 f5 g5 h5
                           a4 b4 c4 d4 e4 f4 g4 h4
                           a3 b3 c3 d3 e3 f3 g3 h3
                           a2 b2 c2 d2 e2 f2 g2 h2
                           a1 b1 c1 d1 e1 f1 g1 h1
                                                  Image:chess_zver_26.png
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   The black knight on e6 is pinned to its king by the white bishop, and
   the white knight is pinned to the queen on b1 by the black rook. Note
   that the knight on b4 is still free to legally move, while the knight
   on e6 cannot legally move.

   When taking and trading pieces, the chess piece point values become
   important. Valuations differ slightly from book to book, but generally,
   taking pawns to be worth one point, knights and bishops are worth three
   points each, rooks are worth five points, and queens are worth nine
   points. Since the king's loss ends the game, it is invaluable (and the
   king is never traded). However, in the endgame when there are few
   pieces left on the board and there is little danger of checkmate, the
   fighting value of the king is equivalent to about four points. The
   actual value and importance of a piece will vary based upon its
   position and the stage of the game. If a player performs a sacrifice
   (e.g. exchange sacrifice), he is choosing to ignore the standard
   valuation of his pieces for positional or tactical gains. The beginning
   player should be aware that points are not an inherent part of the
   game; there is no scoring and chess was played long before the idea of
   assigning points to pieces. Instead, points are used by a player to
   consider whether he will come out materially better than his opponent
   in an exchange of pieces. For instance, to lose two pawns (two points)
   in taking the opponent's knight (three points) puts one ahead in
   material by one point. Such an advantageous exchange of pieces may,
   however, be a poor tactic if it leaves the opponent with an exploitable
   advantage in the way the pieces are positioned on the board.

   Chess combinations and traps do not appear out of thin air. Usually
   they are present because the opponent has certain weaknesses in his
   position. These types of weaknesses include: pinned pieces, overloaded
   pieces, weaknesses around the opponent's king, weak squares,
   unprotected pieces, weak colour complexes, pieces not able to come back
   to defend the king, etc. The weaknesses can then be exploited with a
   chess combination that is often built out of a number of tactical
   "methods". Such weaknesses are often created in the opponent's position
   in the first place by threats, provocative moves, and generally strong
   "positional play", etc. Chess combinations often include a number of
   types of tactics which many middlegame books classify and provide
   examples. Such common tactical methods include pins, forks, skewers,
   discovered attacks (especially checks), zwischenzugs, deflections,
   decoys, sacrifices, forcing moves, undermining, overloading,
   interference and even "quiet moves".
   Two kings and two queens from the Lewis chessmen at the British Museum
   Enlarge
   Two kings and two queens from the Lewis chessmen at the British Museum

   A fork is a situation where a piece is moved such that two opposing
   pieces are attacked (forked) simultaneously. It usually is difficult
   for the other player to protect both of his pieces in one move. Pins
   are used to prevent the movement of an enemy piece by threatening any
   pieces behind it should it move. Skewers are a kind of reverse pin
   where the more valuable piece is placed in front of a less important
   one. A discovered attack (or revealed threat) is where the movement of
   one piece reveals a formerly blocked line of attack for another piece
   of the same colour. For clarification, it should be noted that a "pin"
   is a tactic - the act of pinning the opponent's pieces. But a "pinned
   piece" is a specific type of weakness in the opponent's position, which
   when identified, can be exploited with a tactical combination.

   A few common positional elements which high level chess players
   routinely must assess include pawn structure, king safety, space, and
   control of key squares and groups of squares (e.g. diagonals,
   open-files, dark or light squares, etc.). In addition, there are
   factors such as the two bishops that compensate each other's
   weaknesses. Most middlegame books recommend that once an assessment of
   the elements of the position has taken place, it is then recommended to
   try and form a "plan" to create an advantage. Once a plan is
   formulated, it is then recommended to try and ensure the plan is
   feasible through the process of checking concrete variations.

   Great chess writer Aron Nimzowitsch outlined in the classic work My
   System a number of middlegame positional principles such as "rook on
   the seventh rank", "undermining the pawn chain", "restrain, blockade
   and destroy". This work has influenced generations of modern chess
   players in how they think in the middlegame.

   During the endgame, pawns and kings become relatively more powerful
   pieces as both sides often try to promote their pawns. If one player
   has a large material advantage, checkmate may happen quickly in the
   endgame. If the game is relatively even, endgame tablebases and endgame
   study are essential. Controlling the tempo (time used by each move)
   becomes especially important when fewer pieces are left on the board.
   In some cases, a player will have a material advantage, but will not
   have enough material to force a checkmate. In this case, the game is
   considered a draw by insufficient material.

Alternative ways to play

   Chess is for people of all ages, young and old
   Enlarge
   Chess is for people of all ages, young and old

   Blitz chess is a version of chess where a chess clock is used to limit
   the time control for each player. Generally each side has three to
   fifteen minutes (five is common) for all of its moves. An even faster
   version of chess is known as bullet chess or lightning chess. Bullet
   chess's time controls are less than three minutes. Speed chess requires
   the player to spend less time thinking because if the player's time
   runs out, he loses. When playing at a faster time, computers become
   relatively more powerful than humans.

   If both players use computers to enhance their strength, it is called
   advanced chess.

   Chess can also be played blindfold. In this case the play is conducted
   without the players having sight of the positions of the pieces, or any
   physical contact with them. Moves are communicated via chess notation.
   Some very strong chess players are able to play multiple blindfold
   games simultaneously.

   When two players are separated by great distances they can still play
   chess. Correspondence chess is chess played through the mail, e-mail or
   special correspondence chess servers.

   Today, chess is often played on the internet through the telnet-based
   hosts (such as ICC and FICS) and TCP/IP based servers (such as
   Playchess and WCN).

Variants

   One of many chess variants: Glinski's hexagonal chess.
   Enlarge
   One of many chess variants: Glinski's hexagonal chess.

   Chess variants are forms of chess where the game is played with a
   different board, special fairy pieces or different rules. The number of
   possible chess variants is unlimited. D.B. Pritchard, the author of
   Encyclopedia of Chess Variants, estimates that there are more than two
   thousand chess variants , confining the number to published ones.

   Many chess grandmasters played chess variants and some even invented
   new ones. José Raúl Capablanca feared a "draw death" of chess and
   suggested making the board larger and adding new pieces, such as a
   combination of rook and knight and also a combination of bishop and
   knight. He played a number of test games and finally setlled on an 8x10
   chess variant, Capablanca chess .

   Bobby Fischer objected to what he considered to be an overemphasis on
   memorized chess openings in normal chess, and the Russians fixing
   matches. Thus he devised a formalisation of the variant Shuffle Chess
   in response. In this chess variant, which he originally named Fischer
   Random Chess but is now typically called Chess960, the initial position
   is selected randomly before each game. This random positioning makes it
   almost impossible to prepare the opening play in advance.

History

Origins

   A Persian youth playing chess with two suitors. A form of chess was
   played in Persia as early as the 3rd century.
   Enlarge
   A Persian youth playing chess with two suitors. A form of chess was
   played in Persia as early as the 3rd century.

   Many countries claim to have invented chess in some incipient form. The
   most commonly held view is that chess originated in India , since the
   Arabic, Persian, Greek, Portuguese and Spanish words for chess are all
   derived from the Sanskrit game Chaturanga. In addition, in the past
   only India had all three animals, horse, camel and elephant, in its
   cavalry, which represent knight, bishop and rook in chess. The present
   version of chess played throughout the world ultimately derives from a
   version of Chaturanga that was played in India around the 6th century.
   It is believed that the Persians subsequently created a more
   recognizable version of the game called Shatranj.

   Another theory exists that chess arose from the similar game of Xiangqi
   (Chinese chess), or at least a predecessor thereof, existing in China
   since the 2nd century BC. Scholars who have favored this theory include
   Joseph Needham and David H. Li.

   Chess eventually spread westward to Europe and eastward as far as
   Japan, spawning variants as it went. The game spread throughout the
   Muslim world after the Islamic conquest of Persia. When it entered the
   Muslim world, the names of its pieces largely retained their Persian
   forms but its name became shatranj, which continued in Spanish as
   ajedrez and in Greek as zatrikion, but in most of Europe it was
   replaced by versions of the Persian word shāh = "king". There is a
   theory that this name replacement happened because, before the game of
   chess came to Europe, merchants coming to Europe brought ornamental
   chess kings as curiosities and with them their name shāh, which
   Europeans mispronounced in various ways.

   Chess eventually reached Russia via Mongolia, where it was played at
   the beginning of the 7th century. It was introduced into the Iberian
   Peninsula by the Moors in the 10th century, and described in a famous
   13th century manuscript covering chess, backgammon, and dice named the
   Libro de los juegos. The entrance of chess into Europe is marked by
   changes to the rules, including changes to the moves of the bishops,
   pawns and queen, with the modern form emerging since 15th century.

Development of modern rules and pieces

   Outdoor chess in Budapest, 1990
   Enlarge
   Outdoor chess in Budapest, 1990

   Early on, the pieces in European chess had limited movement; bishops
   could only move by jumping exactly two spaces diagonally (similar to
   the elephant in xiangqi), the queen could move only one space
   diagonally, pawns could not move two spaces on their first move, and
   there was no castling.

   By the end of the 15th century, the modern rules for the basic moves
   had been adopted from Italy: pawns gained the option of moving two
   squares on their first move and the en passant capture therewith,
   bishops acquired their modern move, and the queen was made the most
   powerful piece; consequently modern chess was referred to as "Queen's
   Chess" or "Mad Queen Chess". The game in Europe since that time has
   been almost the same as is played today. The current rules were
   finalized in the early 19th century, except for the exact conditions
   for a draw.

   The most popular piece design, the "Staunton" set, was created by
   Nathaniel Cook in 1849, endorsed by Howard Staunton (a leading player
   of the time), and manufactured originally by Jaques of London. The
   style was officially adopted by Fédération Internationale des Échecs
   (FIDE) in 1924.

Organization

   Chess congress
   Enlarge
   Chess congress

   Chess is an organized sport with structured international and national
   leagues, tournaments and congresses. Chess's international governing
   body is FIDE (Fédération Internationale des Échecs), which has presided
   over the world championship matches for decades. Most countries of the
   world have a national chess organization as well, who in turn are
   members of FIDE.

   FIDE is a member of the International Olympic Committee (IOC), but the
   game of chess has not ever been part of the Olympic Summer or Winter
   Games. Chess does have its own Olympiad, held every two years as a team
   event.

   Correspondence chess tournaments are usually played under the auspices
   of International Correspondence Chess Federation (ICCF). The ICCF
   awards its titles International Master, Senior International Master and
   Grandmaster - these are equivalent to similar titles awarded by FIDE
   for over-the-board chess.

   In order to rank players, both FIDE and ICCF use the Elo rating system
   developed by Arpad Elo.

Competitions

   For most, the ultimate chess competition is the World Chess
   Championship. The current World Chess Champion is Vladimir Kramnik, who
   won a match against Veselin Topalov in 2006. In women's chess, the
   reigning Women's World Champion is Xu Yuhua from China. However, the
   world's highest rated female player Judit Polgar has never participated
   in the Women's World Chess Championship, instead preferring to compete
   with the leading men. Other competitions for individuals include the
   World Junior Chess Championship, the European Individual Championship
   and the National Chess Championships of countries around the world.

   Regular team chess events include the Chess Olympiad and European Team
   Championship. The 37th Chess Olympiad in 2006 was held in Turin, Italy.
   Armenia won the gold in the men's event, and Ukraine took the top medal
   for the women.

   The International Correspondence Chess Federation runs the World
   Correspondence Chess Championships both unrestricted and for women. The
   World Chess Solving Championship is both a team and an individual
   event.

   Besides these top chess competitions, there are thousands of other
   chess tournaments, matches and festivals held around the world every
   year. The most popular would include Spain's Linares event, Monte
   Carlo's Melody Amber tournament, the Dortmund Sparkassen meeting and
   Wijk aan Zee's Corus tournament.

Chess and computers

   The idea of creating a chess playing machine dates back to the
   eighteenth century. Around 1769, the chess playing automaton called The
   Turk became famous before being exposed as a hoax. Serious trials based
   in automatons such as El Ajedrecista were too complex and limited to be
   useful.

   Since the advent of the digital computer in the 1950s, chess
   enthusiasts and computer engineers have built, with increasing degrees
   of seriousness and success, chess-playing machines and computer
   programs. At first considered only a curiosity, the best chess playing
   programs — like Rybka, Hydra etc. — have become extremely strong
   players. In blitz chess, they can beat the best human players; at
   regular time controls battles between the very best chess programs and
   the very best human players have been balanced.

   Garry Kasparov, then ranked number one in the world, played a six-game
   match against IBM's chess computer Deep Blue in February 1996. Deep
   Blue won the first game, but Kasparov convincingly won the match by
   winning three games and drawing two. The six-game rematch in May 1997
   was won by the machine (informally dubbed Deeper Blue) which was
   subsequently retired by IBM..

   Computers are important to today's chess also as seconds with huge
   databases of past games and a high analytical ability, and they also
   allow to play over internet on sites like Free Internet Chess Server or
   Kurnik, which becomes increasingly popular.
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