A chess set in the array, or starting position
In a competitive game, a clock is used. Each player has an equal amount of time for the game.
A modern digital clock
Libro de los juegos, Alfonso X of Castile, showing a Muslim playing a Christian

Chess is a board game for two players.[1] It is played on a square board, made up of 64 smaller squares, with eight squares in each row and column. Each player starts with sixteen pieces: eight pawns, two knights, two bishops, two rooks, one queen and one king.[2] The goal of the game is for each player to try and checkmate the king of the opponent. Checkmate is a threat ('check') to the opposing king which no move can stop. It ends the game.[3][4]

During the game, the two opponents take turns to move one of their pieces to a different square of the board. One player ('White') has pieces of a light color; the other player ('Black') has pieces of a dark color. There are rules about how pieces move, and about taking the opponent's pieces off the board. The player with white pieces always makes the first move.[4] Because of this, White has a small advantage, and wins more often than Black in tournament games.[5][6]

Chess is popular and is often played in competitions called chess tournaments. It is enjoyed in many countries, and is a national hobby in Russia.[7]


A king from the Isle of Lewis chessmen (c. 12th C. British Museum)
Sofonisba Anguissola and her sisters are depicted in The Chess Game, 1555. National Museum in Poznań.

Most historians agree that the game of chess was first played in northern India during the Gupta Empire in the 6th century AD.[8][9] This early type of chess was known as Chaturanga, a Sanskrit word for the military. The Gupta chess pieces were divided, like their military, into the infantry, cavalry, elephants, and chariots. Over time, these pieces became the pawn, knight, bishop, and rook. The English words chess and check both come from the Persian word shāh meaning king.[8]

The earliest written evidence of chess is found in three romances (epic stories) written in Sassanid Persia around 600AD. The game was known as chatrang or shatranj. When Persia was taken over by Muslims (633–644) the game spread to all parts of the Muslim world. Muslim traders carried the game to Russia and Western Europe. By the year 1000, it had spread all across Europe. In the 13th century, a Spanish manuscript called Libro de los Juegos described the games of shatranj (chess), backgammon, and dice.[10]

The game changed greatly between about 1470 to 1495. The rules of the older game were changed in the West so that some pieces (queen, bishop) had more scope, piece development was faster, and the game was more exciting. The new game formed the basis of modern international chess. Chess historians consider this to be the most important change since the game's invention.[8][11]


The rules of chess are governed by the World Chess Federation, which is known by the initials FIDE, meaning Fédération Internationale des Échecs. The rules are in the section Laws of Chess of the FIDE Handbook. FIDE also give rules and guidelines for chess tournaments.[4][12]


Chess is played on a square board divided into eight rows of squares called ranks and eight columns called files, with a dark square in each player's lower left corner.[13] There are 64 squares on a chess board. The colors of the squares are laid out in a checker (chequer) pattern with light and dark squares. To make speaking and writing about chess easy, each square has a name. Rank are numbered from 1 to 8, and each file is lettered from a to h. The letter assigned to a file comes before the number.

its ownbel, such as g1 or f5. The pieces are in white and black sets. The players are called White and Black, and at the start of a game each player has 16 pieces. The 16 pieces are one king, one queen, two rooks, two bishops, two knights and eight pawns.[4]


Definitions: vertical lines are files; horizontal lines are ranks; lines at 45° are diagonals. Each piece has its own way of moving around the board. The X marks the squares where the piece can move.

  • The knight is the only piece that can jump over another piece.
  • No piece may move to a square occupied by a piece of the same color.
  • All pieces capture the same way they move, except pawns.
Moves of the king
Moves of the rook
Moves of the bishop
Moves of the queen
Moves of the knight
Moves of the pawn
  • The king (K for short) can move one square in any direction. The king may not move to any square where it is threatened by an opposing piece. However, the king can move to a square that is occupied by an opponent's piece and capture the piece, taking it off the board.
  • The queen (Q) can move any distance in any direction on the ranks, files and diagonals.
  • The rooks (R) move any distance on the ranks or files.[4]
  • The bishops (B) move diagonally on the board. Since a bishop can only move diagonally, it will always be on the same color square.[14]
  • The knights (Kt or N) move in an "L" shape. Each move must be either two squares along a rank and one square along a file, or two squares along a file and one square along a rank. It is the only piece that can jump over other pieces. Like the other pieces, it captures an opposing piece by landing on its square.
  • The pawns can only move up the board. On its first move a pawn may move either one or two squares forward. A pawn captures one square diagonally, not as it moves: see white circles on its diagram. In some situations, pawns can capture opponent's pawns in a special way called en passant, which means in passing in French (see below).[4]


Most pieces capture as they move. If a piece lands on an opponent's piece, the opposing piece is taken off the board. There are three special cases:

  1. The king cannot be taken (see check and checkmate).
  2. No piece can be taken while castling (see below).
  3. Pawns take one square diagonally.

Check and checkmate

An example of checkmate

If a move that attacks the opposing king is made, the king is said to be 'in check'. The player whose king is in check must make a move that escapes the check. A player can't move into check. The options when a player is in check are moving the king, capturing the threatening piece, or moving another piece between the threatening piece and the king.[15][16]

To win the game one player must checkmate the other player. Checkmate happens when the other player's king is in check and there is no way to get out of check.[4] The word checkmate is often shorted to "mate". Most games end with one of the players resigning (giving up) when their position is so bad that defeat seems inevitable.

Special moves


A chess castling move

Once in every game, each king can make a special move, known as castling. When the king castles, it moves two squares to the left or right. When this happens, the rook is moved to stand on the opposite side of the King.[17] Castling is only allowed if all of these rules are kept:[12]p120

  • Neither piece doing the castling may have been moved during the game.
  • There must be no pieces between the squares the king and the rook.
  • The king may not be currently in check. The king can't pass through any square attacked by the opponent as well. As with any move, castling is not allowed if it would place the king in check.[4]

En passant

En passant

En passant ('in passing' in French) is a special capture. It is only available when a pawn moves forward two squares past an opposing pawn on an adjacent file. The opposing pawn must be on the 5th rank from its own side. Then the opponent's pawn can capture the double-mover as if it had only moved one square forward. This option is open on the next move only.[4]

For example, if the black pawn has just moved up two squares from g7 to g5, then the white pawn on f5 can take it by en passant on g6. The en passant rule was developed when pawns were allowed to make their double move. The rule made it more difficult for players to avoid pawn exchanges and blockade the position. It kept the game more open.


When a pawn moves to its eighth rank, it must be changed for a piece: a queen, rook, bishop, or knight of the same color (player's choice).[18] Normally, the pawn is queened, but in some cases another piece is chosen to get an advantage. This is called 'under-promotion'.[4]

Ways a game may end

Checkmates are rare in competitive chess. The most common ends are decisions made by one or both players.


  • Checkmate. When a king is in check, and cannot get out of it.
  • Resignation. A player may resign at any time, usually because their position is hopeless. A losing player is able to resign by placing their king on its side on the chessboard.
  • Out of time. If player's clock time is over (exceeding the time control). Strictly speaking, this is not part of the rules of the game, but part of the rules of tournament and match chess where chess clocks are used.[4][12]Chapter 8
  • Forfeit: A player who cheats, doesn't follow the rules, or doesn't follow the rules of conduct for a tournament can be forfeited. Sometimes, both players are forfeited.[19]


  • Draw agreed. A game may end in a draw at any time if one player offers a draw and the other accepts.
  • Insufficient material or dead position . A position where no series of legal moves could lead to a mate (example: K+B vs K). The game is drawn.[12]p92
  • Stalemate. If a player cannot make a move, and the player's king is not in check, this is also a draw. This kind of draw is called a stalemate, and is rare.[4]
  • 50-move rule. A game will also end in a draw if no piece is captured and no pawn has moved after fifty moves. This is called the fifty-move rule, and happens late in the game.[20]
  • Threefold repetition. If the exactly same position is repeated three times during a game with the same player to move each time, the player next to move may claim a draw. The game is now drawn. This is called a draw by threefold repetition.[21]

Competition rules

The FIDE rules for competitive chess include all the rules above, as well as several others.[4][12]p92 et seq

Touch and move law

If a player wishes to adjust a piece on the board, they must first say "J'adoube" (I adjust) or the equivalent. Apart from that, if a piece is touched it must be moved if possible. This is the 'touch and move' law.[9]p425[4] If no legal move is possible with the touched piece, the player must make a legal move with another piece.Section 4[12]p90 et seq When a player's hand leaves a piece after moving it then the move is over and may not be changed (if the move was legal).

There are a few famous cases where players appeared to break this rule without being punished. The most famous example was by the then World Champion Garry Kasparov against Judit Polgar in a top-class tournament.[22][23]

Chess clocks

Competitive games of chess must be played with special chess clocks which time a player only when it is their turn to move. After moving, the player presses a button on the clock, which stops the player's clock and starts the opponent's clock. Usually the clocks are mechanical, but some are electronic.[4]Article 6[12]p92 et seq Electronic clocks can be set to various programs, and they can count moves made.[12]chapter 8

Notation for recording moves

Algebraic chess notation

The moves of a chess game are written down by using a special chess notation. This is compulsory for any competitive game.[4]Article 8 & Appendix E Usually, algebraic chess notation is used.[24] In algebraic notation, each square has one name, regardless of whether you are looking from White's side of the board or Black's. Here, moves are written in the format of: initial of piece moved – file where it moved – rank where it moved. For example, Qg5 means "queen moves to the g-file and 5th rank" (that is, to the square g5). If there are two pieces of the same type that can move to the same square, one more letter or number is added to show the file or rank from which the piece moved, e.g. Ngf3 means "knight from the g-file moves to the square f3". The letter P showing a pawn is not used, so that e4 means "pawn moves to the square e4".

If the piece makes a capture, "x" is written before the square in which the capturing piece lands on.[25] Example: Bxf3 means "bishop captures on f3". When a pawn makes a capture, the file from which the pawn left is used in place of a piece initial. For example: exd5 means "pawn captures on d5."

The "Scholar's mate"

If a pawn moves to its eighth rank, getting a promotion, the piece chosen is written after the move, for example e1Q or e1=Q. Castling is written by the special notations 0-0 for kingside castling and 0-0-0 for queenside. A move which places the opponent's king in check normally has the notation "+" added. Checkmate can be written as # or ++. At the end of the game, 1-0 means "White won", 0-1 means "Black won" and ½-½ is a draw.

In print, figurines (like those in diagrams, but smaller) are used for the pieces rather than initials. This has the advantage of being language-free, whereas the initials of pieces are different in every language. Typefaces which include figurines can be purchased by chess authors. Also, basic notes can be added by using a system of well-known punctuation marks and other symbols.[25] For example: ! means a good move, !! means a very good move, ? means a bad move, ?? a very bad move (sometimes called a blunder), !? a creative move that may be good, and ?! a doubtful move. The purpose of these methods is to make publications readable in a wider range of countries. For example, one kind of a simple "trap" known as the Scholar's mate, as in the diagram to the right, may be recorded:

1. e4 e5
2. Qh5?! Nc6
3. Bc4 Nf6?? (3...Qe7 would prevent the mate, with 4...Nf6 next move)
4. Qxf7# 1-0

With figurines in place of the initials, the chess notation is understood universally.

Playing arena

Players are not allowed to smoke in the playing area. They are only allowed to smoke in areas designated by the organiser. Mobile phones may not be used or even switched on. In many tournaments players may not bring mobile phones into the playing area. Players cannot use any source of advice during a game, such as other players or chess books, nor analyse the game on a device. These and other matters are covered by the FIDE Laws on the conduct of the players.[4]Article 12

Stages of a game

A game is divided into three stages: the opening, the middlegame, and the endgame.


The first moves of a chess game are called the opening.[26][27] A chess opening is a name given to a series of opening moves. Recognized patterns of opening moves are openings and have been given names such as the Ruy Lopez or Sicilian defence. They are listed in reference works such as the Encyclopaedia of Chess Openings. There are dozens of different openings. They range from gambits, where material, such as pawns are offered for fast development (e.g. the King's Gambit), to slower openings, which lead to a maneuvering type of game (e.g. the Réti opening). In some opening lines, the sequence thought best for both sides has been worked out to 20–30 moves; most players avoid such lines.[28] Expert players study openings throughout their chess career, as opening theory keeps on developing.

The basic aims of the opening phase are:[29]

  • Development: to place (develop) the pieces (mostly bishops and knights) on useful squares where they will have the most powerful impact on the game.[30]
  • Control of the center: the center is the most important part of the board. The player who controls the center can move their pieces around freely. The opponent, on the other hand, will find their pieces cramped, and difficult to move about.
  • King safety: keeping the king safe from danger. Castling (see section above) can often do this.
  • Pawn structure: pawns can be used to control the center. Players try to avoid making pawn weaknesses such as isolated, doubled or backward pawns, and pawn islands – and to force such weaknesses in the opponent's position.

White, by virtue of the first move, begins the game with a better chance of winning. Black normally tries to equalize or to get counterplay during the game.


The middlegame is the part of the game where most pieces have been developed. It is where most games are won and lost. Many games will end in resignation before the endgame takes place.

A middlegame position has a structure. That structure is determined by the opening. The simplest way to learn the middlegame is to select an opening and learn it well (see examples in English Opening and French Defence).

These are some things to look for when analyzing a middlegame position:

  • Material: changes in the balance of material are critical. To lose a piece for nothing is enough to lose a game. If the players are evenly matched, then a rough material balance of pieces is normal. Material balance is often quite static: it does not change for many moves.
  • Development: the opening may have left one player with a lead in development. That player has the initiative, and may attack before the opponent can get his pieces out. It is a temporary asset; if a lead in development is not used effectively, it will disappear.
  • The centre: in the centre pieces have their greatest effect, and some (such as the knight) attack more squares in the centre than at the sides. The player who controls the centre will almost always have the advantage.
  • Mobility: a position is mobile if the pieces can get to their ideal squares. Almost all middle game positions have some limitations to mobility. Look for open files for the rooks, and open diagonals for the bishops. Knights are best placed on outposts, where they cannot easily be dislodged.
  • King safety: ideally, the king should be castled and kept behind a screen of pawns. If a king is weak, it may targeted for an attack by the opponent.
  • Pawns: they provide the skeleton of a position. They move slowly, and may become blocked for many moves. Everything takes place around the pawns. Different openings produce different pawn structures. In this way, openings influence the whole game (François-André Danican Philidor: "Pawns are the soul of chess").
King's Indian, main line

Here is an example from the borderline between opening and middlegame. In the diagram to the left, White will mainly play on the queenside, while Black will play on the kingside.

If White to play, he may wish to stop Black's threat of playing 10...Nf4. He can do this by playing 10.g3, or by playing 10.Re1 so that if 10...Nf4 11.Bf1 will preserve the bishop (in this position it is an important defensive piece). However, White may try to plough ahead with 10.c5, the key move on the queenside. ChessBase shows that the number of tournament games with these choices were:

10.Re1: 2198
10.g3: 419
10.c5: 416

The database also shows that the overall results were significantly better for 10.Re1. During a middlegame, the player should note the features of the position on the board, and formulate a game plan. The opponent will try to interfere with the plan or gain counterplay.


The endgame is the part of the game when there are few pieces left on the board. There are three main strategic differences between earlier parts of the game and the endgame:

  • Pawns: during the endgame, pawns become decisive in the result of a game. In the endgame, both players try to promote their pawns by advancing them to the first or last ranks, depending on which side is advancing. When a pawn reaches the end of the board, it can promote to a queen; this action is called queening. It can also promote to a rook, knight, or bishop, called underpromotion, which may be favorable under certain circumstances.
  • Kings: becomes a strong piece in the endgame. The king can be brought towards the center of the board. There, it can support its own pawns, attack the opponent's pawns, and oppose the opponent's king.
  • Draws: in the endgame, a game may be drawn because there are too few pieces on the board to allow a player to win.

Endgame positions are easier to analyze than middlegames, as there are fewer pieces on the board. Many endgame positions can be won by force. A drawn endgame is one that is legally drawn (checkmate is impossible), or drawn by chess experience (drawn with best play by both sides). All endgames in master chess revolve around the borderline between winning and drawing. Generally, once a 'textbook' drawn position is reached, the players will agree a draw.

Endgames can be studied according to the types of pieces that remain on the board. For example, king and pawn endgames have only kings and pawns on one or both sides, and the task of the stronger side is to promote one of the pawns. Other endings are studied according to the pieces on board other than kings, e.g. rook and pawn versus rook endgame.[9]

Basic checkmates

Basic checkmates are positions in which one side has only a king and the other side has one or two pieces, enough to checkmate the opponent's king. They are usually learned at the beginner stage. Examples are mate with K+Q v K; K+R v K; K+2B v K; K+B&N v K (this one is quite difficult).

Chess and computers

There are two types of chess programs. One is to play against you; the other is to help you become a better player by learning more. The two types can be made to work together, though they have different functions.

Chess engines

Chess engines are computer systems that can play chess games against human opponents. Quite a number have been devised; they can play at master level, though their processes are quite different from a human being.[9]p87

Every year brings new advances, which if listed here would soon be out of date. Best advice is to go to English Wikipedia, which keeps an up-to-date chart of the leading software: [1].

Chess databases

Chess databases give access to the recorded history of master chess games. There are two components: software, which lets one search and organise the database material, and the actual database. There are usually over a million games in a given database.

In practice, databases are used for two purposes. First, for a player to train his/her ability at specific openings. Second, to look up specific opponents to see what they play, and prepare against them beforehand.

The existence of chess databases is one of the reasons players can achieve mastery at an young age.


ChessBase is the biggest database, and widely used by masters. Although it can be used online, most users download the software and data onto their computer. If that computer happens to be a laptop, then they might take the laptop to tournaments to help prepare for games. Players cannot use computers or any other aid during games, so much of the preparation goes on before a game. ChessBase has to be purchased, and it is not cheap.[31]

New in Chess

This is a Dutch magazine for advanced players, which runs an online database called NicBase as part of its services. NicBase is free, and has over a million games.[32]

Chessgames runs an online database of games. It is mostly free; full access to all its facilities costs a subscription. It has over half a million games on its database.[5]

Online playing sites

There are websites which a player can join (for a fee) and play on line. In this case, the subscriber will play against other subscribers, not a computer. All standards of players are amongst the members, and various events are on offer at different rates of play. Online chess websites include:

  • Lichess
  • Internet Chess Club[33]
  • Playchess[34]

Further reading

  • Burgess, Graham and John Nunn 1998. The mammoth book of the world's greatest chess games. Carroll & Graf. ISBN 978-0786705870
  • Chandler, Murray 1998. How to beat your dad at chess. Gambit, London. ISBN 1-901983-05-6 (Improvers)
  • Chandler, Murray 2004. Chess for children. Gambit, London. ISBN 978-1904600060 (Beginners)
  • Euwe, Max and Kramer H. 1994. The middlegame, books I and II. Hays. ISBN 978-1880673959 and ISBN 978-1880673966 This goes further than improvers need, but might be used by chess teachers as a source of classic positions.
  • King, Daniel 2000. Chess: from first moves to checkmate. Kingfisher, London. Illustrated, 64 pages. (Beginners, children).
  • Polgar, Laszlo 2006. Chess: 5334 problems, combinations and games. Illustr. ed, Black Dog & Leventhal. ISBN 978-1579125547
  • Pritchard, David Brine 2008. The right way to play chess. 8th ed, Right Way. ISBN 978-0716021995 (Beginners > impovers)
  • Silman, Jeremy 1997. How to reassess your chess. 3rd ed expanded, Siles. ISBN 9781890085001
  • Tarrasch, Siegbert (1994). The game of chess. Algebraic edition. Hays Publishing. ISBN 1-880673-94-0. OCLC 31152893.
  • Ward, Chris 1994. Opening play (think like a chess master). Batsford, London. ISBN 0713475110
  • Wolff, Patrick 2005. The complete idiot’s guide to chess. 3rd ed, Alpha, New York. (Beginners > improvers)
  • Znosko-Borovsky, Eugene 1980. The middle game in chess. Dover. ISBN 978-0486239316 (Improvers > intermediate)


These are endgames for improvers, based on reviews by John Watson.[35]

Chess Media

Related pages


  1. Abate, Frank R. (ed) 1997. The Oxford desk dictionary and thesaurus. ISBN 0-19-511214-8
  2. Costello, Robert E. et al. (eds) 2001. Macmillan dictionary for children. Simon & Schuster, New York. ISBN 0-689-84323-2
  3. Paton, John et al. (eds)1992. The Kingfisher children's encyclopedia. Kingfisher Books, New York. ISBN 1-85697-800-1
  4. 4.00 4.01 4.02 4.03 4.04 4.05 4.06 4.07 4.08 4.09 4.10 4.11 4.12 4.13 4.14 4.15 4.16 "Laws of Chess". FIDE. Retrieved 2008-11-26.
  5. 5.0 5.1 Chessgames "Chess Opening Explorer". Retrieved 2010-05-25.
  6. Rowson, Jonathan (2005). Chess for Zebras: thinking differently about black and white. Gambit Publications. p. 193. ISBN 1-901983-85-4.
  7. Gifford, Clive and Lisa Clayden (2002). Family flip quiz: Geography. Essex: Miles Kelly. ISBN 1-84236-146-5.
  8. 8.0 8.1 8.2 Murray H.J.R. (1913). A history of chess. Benjamin Press (first published by Oxford University Press). ISBN 0-936317-01-9. OCLC 13472872.
  9. 9.0 9.1 9.2 9.3 Hooper D. and Whyld K. 1992. The Oxford companion to chess. 2nd ed, Oxford University Press.
  10. Audubert, Pierre 1978. Das spanische Schachbuch des Königs Alfons des Weisen vom Jahr 1283. Idion, Munchen.
  11. Eales, Richard. 1983. Chess: the history of a game. Batsford, London.
  12. 12.0 12.1 12.2 12.3 12.4 12.5 12.6 12.7 Reuben, Stewart 2005. The chess organiser's handbook. 3rd ed, incorporating the FIDE Laws of Chess. Harding Simpole, Devon.
  13. "Chess Basics". Archived from the original on 13 April 2010. Retrieved 1 April 2010.
  14. "Chess Moves - How chess pieces move - chess piece movements". Retrieved 1 April 2010.
  15. "Checkmate in Chess". Archived from the original on 24 March 2010. Retrieved 1 April 2010.
  16. United States Chess Federation. (2003). U.S. Chess Federation's official rules of chess. Just, Tim., Burg, Daniel B. (5th ed.). New York. ISBN 0-8129-3559-4. OCLC 52859422.
  17. "Castling, by Chess Corner". chess corner. Retrieved 1 April 2010.
  18. Robert Harrison. "Chess tips: How to promote a pawn". Archived from the original on 21 May 2011. Retrieved 25 May 2010.
  19. "Fide Laws of Chess taking effect from 1 January 2018". FIDE. Retrieved 18 February 2020.
  20. "Learn Chess:Check and Checkmate". 2010. Retrieved 12 March 2010.
  21. "Chess Rules :: Draw threefold repetition". Archived from the original on 9 April 2010. Retrieved 1 April 2010.
  22. Peters, Jack (Jan 5, 1995). Chess Highlights of 1994. p. 27. 
  23. Berry, Jonathan (Mar 19, 1994). Victory boosts Karpov's rating. Toronto. p. A18.  Berry, himself a Fide Master and International Arbiter, describes the incident: "Mr. Kasparov picked up his knight at d7 and placed it on c5. 'Touch & move' requires a player to move a touched piece, but the move is not over until the hand leaves the piece. Seeing that 37.Bb7-c6 would be bad for Black, Mr. Kasparov instead put the knight on f8. However, the way Miss Polgar saw it, Mr. Kasparov's hand did leave the piece on c5. Accounts diverge from there. We do know that Spanish TV recorded the game and that there were several spectators, some of whom thought that Mr. Kasparov removed his hand from the knight at c5".
  24. See paragraph E. Algebraic notation in:
    "E.I.01B. Appendices". FIDE. Retrieved 2008-11-26.
  25. 25.0 25.1 "Chess Notation". Roger McIntyre. Huntsville Chess Club. Archived from the original on 23 January 2010. Retrieved 25 May 2010.
  26. "A beginner's garden of chess openings". Archived from the original on 5 March 2005. Retrieved 1 April 2010.
  27. "CHESSOPS: A basic guide to chess openings". Peter Hobbs. Retrieved 2010-05-25.
  28. Collins, Sam (2005). Understanding the chess openings. Gambit Publications. ISBN 1-904600-28-X. OCLC 57484838.
  29. Tarrasch, Siegbert (1987). The game of chess. Courier Dover Publications. ISBN 0-486-25447-X. OCLC 15631832.
  30. "chessguru". BBC News. Retrieved 7 March 2010.
  31. "ChessBase Service and Download". Retrieved 25 May 2010.
  32. NicBase "NicBase online". New In Chess. Archived from the original on 2010-04-02. Retrieved 2010-05-25.
  33. "The Internet Chess Club". Internet Chess Club. Retrieved 2010-05-25.
  34. "Playchess". ChessBase. Archived from the original on 2011-02-24. Retrieved 2010-05-25.
  35. John Watson's reviews "John Watson Chess Book Reviews". The Week in Chess. Archived from the original on 2011-05-14. Retrieved 2010-05-25.