If players wish 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. If no legal move is possible with the touched piece, the player must make a legal move with another piece. 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.
Competitive games of chess must be played with special chess clocks which time a player only when it is his/her turn to move. The essence is that a player has to make a certain number of moves in a certain total time. After moving, the player presses a button on the clock. This stops the player's clock, and start's the opponent's clock. Usually the clocks are mechanical, but some are electronic. Electronic clocks can be set to various programs, and they can count moves made.
The moves of a chess game are written down by using a special chess notation. This is compulsory for any competitive game. Usually algebraic chess notation is used. In algebraic notation, each square has one and only one name (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. 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."
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. 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, this would be understood by players everywhere.
Players may not smoke in the playing area, but only in areas designated by the organiser. Mobile phones may not be used or even switched on. Players may not use any sources of advice, and may not analyse on any device. These and other matters are covered by the FIDE Laws on the conduct of the players.
Chess is an easy game to learn the moves, but a difficult game to master. Strategy is an important part of the game. First of all comes the "openings", about which a great deal is now known. The best-known move, the King's Pawn opening, is the white player moving his king's pawn on e2 forward two spaces to e4. Black can reply to that move in various ways.
The first moves of a chess game are called the "opening". 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 a pawn, say, is 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, but most players avoid such lines. Expert players study openings throughout their chess career, as opening theory keeps on developing.
The basic aims of the opening phase are:
Players think, and chess databases prove, that White, by virtue of the first move, begins the game with a better chance. Black normally tries to equalise, or to get some counterplay.
The middlegame is the part of the game after most pieces have been developed. It is where most games are won and lost. Many games will end in resignation even before an endgame takes place.<ref name="H/W">Hooper D. and Whyld K. 1992. "The Oxford companion to chess". 2nd ed, Oxford University Press.</ref>
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 looking at a middlegame position:
Here is an example from the borderline between opening and middlegame. In the diagram to the left, White will operate mainly on the Q-side, and Black on the K-side.
White, to play, may wish to cope with Black 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 an important defensive piece). Or maybe White will plough ahead with 10.c5, the key move on the Q-side.
ChessBase shows that the number of tournament games with these choices were:
The data base also shows that the overall results were significantly better for 10.Re1. What the player does is note the features on the board, and formulate a plan which takes the features into account. Then the player works out a sequence of moves. Of course, in practice, the opponent is interfering with the plan at every step!
The endgame (or "end game" or "ending") 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 endgame:
All endgame positions can be put into two camps. On the one hand are positions which may be won by force. On the other hand, are positions which are drawn, or which should be drawn. The ones that are drawn for certain may be legally drawn (mate could not happen) or drawn by chess experience (no sane defence could lose). 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; otherwise they play on.
Endgames can be studied according to the types of pieces that remain on 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.