Chess

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The game of chess is the most popular board game in the western world. It is played between two opponents on an 8-by-8 board. One player directs the white pieces and the other player the black pieces. White starts and then the players move alternatingly. The object of the game is to achieve checkmate, a situation where the opponent's king cannot escape capture.

Chess is especially popular for its complexity. The number of legal positions in chess is estimated to be 1043; the number of possible games is a lot larger and greatly exceeds the estimated number of particles in the observable universe.

Rules

Each player is given sixteen pieces which are arranged in the opening position on a 64-square chess board. The pieces are a king, a queen, two rooks, two bishops, two knights and eight pawns. The players alternate moves (one has the white pieces and moves first, the other has the black pieces).

Check, Checkmate:

The object of the game is checkmate, a situation where the opponent's king is threatened with capture and has no way out. A position in which the king is threatened with capture (but has a way out) is called check; a player can never move a king into and must always rescue a king from such a position.

Draw:

The game ends draw on one of these conditions:

  • If the player to move is not in check and has no legal move (stalemate).
  • If there is no possibility for either player to mate the opponent (for example, because there are insufficient pieces remaining).
  • By agreement of the players.

Each player can request a draw on one of these conditions:

  • If fifty moves have been played by each player without a piece being taken or a pawn moved.
  • If the same board position has been repeated three times, with the same player to move and all pieces having the same rights to move (castling and en passant, see below).
  • With less than two minutes left in the last time period a player can request a draw if the opponent makes no effort to win with "normal means". This is decided by an arbiter and only used in tournament play.

Moving:

A move is

  • Moving a piece from one square to another empty square.
  • Moving a piece to a square occupied by an opposing piece and removing the enemy piece (capture).
  • Castling (see below).
  • Promotion (see pawn below).
  • En passant (see pawn below).

The king can move to any adjacent square, either diagonally, vertically or horizontally. The king must not be left in check, nor may he move to a square where he could be taken.

Queen, rook and bishop move onto any square along straight lines unless blocked by a friendly piece or by an opposing piece, which they can capture.
The rooks can move in a straight line only in non-diagonal directions (along ranks and files). The bishops can move in a straight line only in diagonal directions. The queen can move in a straight line in any of eight directions, thus combining the power of the rook and the bishop. This makes the queen the most powerful piece.

The knight moves by 'jumping' in an L-shaped pattern, two squares in any non-diagonal direction and then one square perpendicular. The knight is the only piece that may jump over other pieces to reach its destination.

Pawns move straight forward by one square (or two from their starting position). They capture diagonally forward. If a pawn reaches the 8th rank, it must be promoted to any other piece of its own color except a king immediately.

A pawn moving two squares can be captured by opposing pawns that could have captured it if it had only moved on square. This may only be done on the next move.
A black pawn on the fourth rank can capture a white pawn making it´s initial (two-step) move on a square directly besides the black pawn. A white pawn on the fifth rank can capture a black pawn making the corresponding move.
This en passant move was added soon after the two-space initial pawn move to preserve the interaction of pawns.

Castling involves moving the king two spaces toward a rook of the same color and moving the rook to the space immediately beyond the king. It protects the king and brings out the rook for action. It must be the first move that the king and the rook make, there must be no other pieces in the way, and the king cannot move into, out of, or through check.

:   :   :   :   :   :   :   :   :       :   :   :   :   :   :   :   :   :
+---+---+---+---+---+---+---+---+  __\  +---+---+---+---+---+---+---+---+
| R |   |   |   | K | B |   | R |    /  |   |   | K | R |   | B |   | R |
+---+---+---+---+---+---+---+---+       +---+---+---+---+---+---+---+---+
Queen-side castling
:   :   :   :   :   :   :   :   :       :   :   :   :   :   :   :   :   :
+---+---+---+---+---+---+---+---+  __\  +---+---+---+---+---+---+---+---+
| R |   | B | Q | K |   |   | R |    /  | R |   | B | Q |   | R | K |   |
+---+---+---+---+---+---+---+---+       +---+---+---+---+---+---+---+---+
King-side castling

In tournament play and for quick chess, a chess clock is used; each player presses a button after every move and the clock keeps track of the time remaining for each player. If a player runs out of time before the game is decided in some other way, that player loses the game. In correspondence chess, the moves are sent by mail and every player is given a set number of days per move.

Maybe some diagrams for all pieces and special moves will help :)

Strategy and Tactics

Some rules of thumb for playing well are given in the Chess Strategy and Tactics article.

The world of Chess

Lists of World Champions and famous players are available.

The world organization of chess players is the FIDE which organizes regular world chess championships. In recent years, some players complained about arbitrary decisions by FIDE and left to start competing organizations.

Strong players are awarded the lifetime titles "International Master" and "Grandmaster" by FIDE according to well-defined rules.

History

Chess originated from the Indian game Shatranj, about 1400 years ago. This game is related to xiang4 qi2 (象棋 Chinese Chess) in China, and Shogi in Japan. The game reached Russia via Mongolia, where it was played at the beginning of the 7th century. From India it migrated to Persia, and spread throughout the Islamic world after the muslim conquest of Persia. It was introduced into Spain by the Moors in the 10th century, where a famous games manuscript covering chess, backgammon, and dice, named the Libros de las Juegos, was written under the sponsorship of Alphonso X of Spain during the 13th century. Chess reached England in the 11th century, and evolved through various versions such as Courier.

By the end of the 15th century, the modern rules were adopted: pawns could move two squares on their first move, bishops could move diagonally arbitrary far (before, they jumped three squares diagonally) and the queen was allowed to move arbitrary far in every direction (before, she could only move one square diagonally). The game in Europe since that time has been almost the same as is played today. The current rules were completely finalized in the early 19th century.

The most popular piece design, the "Staunton set", was created by Nathaniel Cook in 1849, endorsed by the then leading player Staunton, and officially adopted by FIDE in 1924.

The title "Grandmaster" was created by Russian Tsar Nicholas II who first awarded it after a tournament in Saint Petersburg which he had funded.

Famous people who were avid chess players

Computer chess

Chess enthusiasts and computer engineers have attempted to build, with increasing degrees of seriousness and success, chess-playing machines for over a century. Their motivations can essentially be consolidated into two: firstly, to build a machine to play chess with for solo entertainment, and secondly, to investigate chess as a problem which might provide some insight into human cognition. In this view, the history of computer chess is both a spectactular success and a virtually complete failure. Chess-playing computers are available for negligible cost, and even the free gnuchess plays a game that, with the aid of virtually any modern personal computer can defeat most master players under tournament conditions. However, to the surprise and disapopintment of many, chess has taught us little about building machines that think offer human-like intelligence, or indeed do anything except play excellent chess.

  • fill in early history etc.*

In May 1997, a computer (IBM's updated Deep Blue) defeated the then reigning world champion Gary Kasparov in a match. IBM keeps a web site of the event at http://www.chess.ibm.com. While not an official world championship, the outcome of the match is often taken to mean that the strongest player in the world is a computer. Such a claim is open to strong debate, as there are other players whose playing style is recognised as more effective against other computer opponents, and it was impossible for Kasparov to prepare to play the machine as he would against a human opponent, as the computer's programming was adjusted between prior matches and the Kasparov match. Conversely, if the machine's programming was left fixed it would have been easy for Kasparov to figure out play lines where the machine is weaker and play to those weaknesses - thus, a truly fair match is very difficult to arrange. IBM retired Deep Blue after the match and it has not played since. However, given that computer hardware and chess algorithms have continued to improve since 1997 it seems likely that an equivalent effort would produce a computer that was more unambiguously stronger than the best human player.

It should be noted in all such speculation that computer chess is not of great academic interest to researchers in artificial intelligence. Chess-playing programs essentially explore huge numbers of potential future moves by both players and apply a relatively simple evaluation function to the positions that result. Such methods are useless for most other problems artificial intelligence researchers have tackled, and are believed to be very different from how human chess players select their moves. Minor variations to the rules would either make chess a trivially easy task for a computer to win, or conversely leave even elaborate computers easy pickings for amateur players. Therefore, the fact that the best efforts of chess masters and computer engineers are so finely balanced should probably be viewed as an amusing quirk of fate rather than the profound comment on thought that many in the past, including some of the early theorists on machine intelligence, thought it to be.

Composition chess

needs to be filled in

Variants

There are many variants of chess. A few of these include: suicide, where capturing moves are mandatory and the object is to lose all pieces, Fischer Random where the placement of the pieces on the 1st and 8th rank is randomized to disemphasize the value of opening theory, bughouse or tandem where two teams of two players face each other on two boards, the team players play different colors and the pieces captured by one partner can be placed on the board by the other instead of moving, advanced chess where the players are allowed to consult a computer, and Kriegspiel where each player does not know where the opponent's pieces are but can deduce them with information from a referee.

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