Algebraic notation (chess)

Algebraic notation (or AN) is a method for recording and describing the moves in a game of chess. It is based on a system of coordinates to uniquely identify each square on the chessboard. (The term "algebraic notation" is in fact a misnomer as it is unrelated to algebra.) It is now standard among all chess organizations and most books, magazines, and newspapers. In English-speaking countries, the parallel method of descriptive notation was generally used in chess publications until about 1980. A few older players still use descriptive notation but it is no longer recognized by FIDE.

Algebraic notation exists in various forms and languages and is based on a system developed by Philipp Stamma. Stamma used the modern names of the squares, but he used p for pawn moves and the original file of a piece (a through h) instead of the initial letter of the piece name.^[1] This article describes standard algebraic notation (SAN) required by FIDE.

Naming the squares

Each square of the chessboard is identified by a unique coordinate pair—a letter and a number. The vertical columns of squares, called files, are labeled a through h from White's left (the queenside) to right (the kingside). The horizontal rows of squares, called ranks, are numbered 1 to 8 starting from White's side of the board. Thus each square has a unique identification of file letter followed by rank number. (For example, White's king starts the game on square e1; Black's knight on b8 can move to open squares a6 or c6.)

Naming the pieces

Each piece type (other than pawns) is identified by an uppercase letter. English-speaking players use the letters K for king, Q for queen, R for rook, B for bishop, and N for knight (since K is already used). S (from the German Springer) was also used for the knight in the early days of algebraic notation and is still used in chess problems (where N stands for the nightrider, a popular fairy chess piece).

Players who speak other languages may employ different letters, for example, French-speaking players use F for bishop (from fou). In chess literature, especially that intended for an international audience, the language-specific letters are often replaced by universal icons for the pieces, for example, Nf3 is represented as ♞f3. This style known as figurine algebraic notation.

Pawns are not identified by uppercase letters, but rather by the absence of one. Distinguishing between pawns is not necessary for recording moves, since only one pawn can move to a given square. (Pawn captures are an exception and indicated differently as explained below.)

Notation for moves

Each move of a piece is indicated by the piece's uppercase letter, plus the coordinate of the destination square. For example, Be5 (move a bishop to e5), Nf3 (move a knight to f3), c5 (move a pawn to c5—no piece letter in the case of pawn moves).

Notation for captures

When a piece makes a capture, an "x" is inserted immediately before the destination square. For example, Bxe5 (bishop captures the piece on e5). When a pawn makes a capture, the file from which the pawn departed is used to identify the pawn. For example, exd5 (pawn on the e-file captures the piece on d5). A colon (:) is sometimes used instead of "x", either in the same place the "x" would go (B:e5) or at the end (Be5:).

En passant captures are indicated by specifying the capturing pawn's file of departure, the "x", the destination square (not the square of the captured pawn), and (optionally) the suffix "e.p." indicating the capture was en passant.^[2] For example, exd6e.p.

Some texts, such as the Encyclopaedia of Chess Openings, omit indication that any capture has been made. (For example, Be5 instead of Bxe5; ed6 instead of exd6 or exd6e.p.) When it is unambiguous to do so, a pawn capture is sometimes described by specifying only the files involved (exd or ed). These shortened forms are sometimes called minimal or abbreviated algebraic notation.

Disambiguating moves

When two (or more) identical pieces can move to the same square, the moving piece is uniquely identified by specifying the piece's letter, followed by (in descending order of preference):

1. the file of departure (if they differ); or
2. the rank of departure (if the files are the same but the ranks differ); or
3. both the file and rank (if neither alone is sufficient to identify the piece—which occurs only in rare cases where one or more pawns have promoted, resulting in a player having three or more identical pieces able to reach the same square).

For example, with knights on g1 and d2, either of which might move to f3, the move is specified as Ngf3 or Ndf3, as appropriate. With knights on g5 and g1, the moves are N5f3 or N1f3. As above, an "x" can be inserted to indicate a capture, for example: N5xf3. Another example: two rooks on d3 and h5, either one of which may move to d5. If the rook on d3 moves to d5, it is possible to disambiguate with either Rdd5 or R3d5, but the file takes precedence over the rank, so Rdd5 is correct. (And likewise if the move is a capture, Rdxd5 is correct.)

Pawn promotion

When a pawn moves to the last rank and promotes, the piece promoted to is indicated at the end of the move notation, for example: e8Q (promoting to queen). Sometimes an equals sign or parentheses are used: e8=Q or e8(Q), but neither format is a FIDE standard. In Portable Game Notation (PGN), pawn promotion is always indicated using the equals sign format (e8=Q).

In older books, pawn promotions can be found using a forward slash: e8/Q.

Draw offer

In FIDE Laws of Chess,^[3] an equals sign with parentheses, "(=)", is used to write the offer of a draw on the score sheet next to a move, but this is not part of algebraic notation.^[4]

Castling

Castling is indicated by the special notations 0-0 (for kingside castling) and 0-0-0 (queenside castling).

The notation 0-0-0-0 was once used in a puzzle composed by Tim Krabbé to indicate a king castling vertically across the board with a promoted pawn which had become a rook on the e-file but not yet moved. FIDE subsequently amended its rules in 1972 to disallow this.^[5]

While the FIDE Handbook, appendix C.13^[6] uses the digit zero (0-0 and 0-0-0), PGN requires the uppercase letter O (O-O and O-O-O).

Check and checkmate

A move that places the opponent's king in check usually has the symbol "+" appended. Or sometimes a dagger (†) is used, or the abbreviation "ch". Double check is commonly indicated the same as check, but is sometimes represented specially as "dbl ch", or in older books as "++". The Encyclopedia of Chess Openings omits any indication of check.

Checkmate at the completion of moves can be represented by the symbol "# " (some use "++" instead, but the USCF recommends "# "). Or the word mate is commonly used. Occasionally the double dagger (‡) is seen. Checkmate is also represented by "≠" by Apple Inc.

End of game

The notation 1–0 at the completion of moves indicates that White won, 0–1 indicates that Black won, and ½–½ indicates a draw.

Often there is no indication regarding how a player won or lost (other than checkmate, see above), so simply 1–0 or 0–1 may be written to show that one player resigned or lost due to time control. Sometimes direct information is given by the words "White resigns" or "Black resigns", but this is not considered part of the notation, rather a return to the surrounding narrative text.

Notation for a series of moves

A game or series of moves is generally written in one of two ways.

	a	b	c	d	e	f	g	h
8									8
7									7
6									6
5									5
4									4
3									3
2									2
1									1
	a	b	c	d	e	f	g	h

Position after 1.e4 e5 2.Nf3 Nc6 3.Bb5 a6

• In two columns, as White/Black pairs, preceded by the move number and a period:

  1. e4 e5

  2. Nf3 Nc6

  3. Bb5 a6

• Horizontally:

  1. e4 e5 2. Nf3 Nc6 3. Bb5 a6

Moves may be interspersed with commentary (annotations). When the score resumes with a Black move, an ellipsis (...) fills the position of the White move, for example:

1. e4 e5 2. Nf3

White attacks the black e-pawn.

2... Nc6

Black defends and develops simultaneously.

3. Bb5

White plays the Ruy Lopez.

3... a6

Black elects Morphy's Defence.

Piece names in various languages

The table contains names for all the pieces as well as the words for chess, check, and checkmate in several languages:^[7]

Kindred notations

Besides the FIDE standard (or short) algebraic notation (SAN) already described, several similar systems are in use for their own particular advantages.

Figurine algebraic notation

Figurine algebraic notation (or FAN) is a widely used variation of algebraic notation which substitutes a piece symbol for the letter representing a piece, for example: ♞c6 in place of Nc6. (Pawns are omitted.) This enables moves to be read independent of language.

The Unicode Miscellaneous Symbols set includes all the symbols necessary for FAN. In order to display or print these symbols, one has to have one or more fonts with good Unicode support installed on the computer, that the Web page, or word processor document, etc., uses.^[12]

Long algebraic notation

Some computer programs (and people) use a variant of algebraic chess notation termed long algebraic notation or fully expanded algebraic notation. In long algebraic notation, moves specify both the starting and ending squares separated by a hyphen, for example: e2-e4 or Nb1-c3. Captures are still indicated using "x": Rd3xd7.

The long notation takes more space and thus is not as commonly used. However, it has the advantage of clarity, particularly for less-skilled players or players learning the game. Some books using primarily short algebraic notation use the long notation instead of the disambiguation forms described earlier.

A form of long algebraic notation (without hyphens) is also notably used by the Universal Chess Interface (UCI) standard, which is a common way for graphical chess programs to communicate with chess engines (e.g. for AI).

ICCF numeric notation

In international correspondence chess the use of algebraic notation may cause confusion, since different languages employ different names (and therefore different letters) for the pieces; hence the standard for transmitting moves in this form of chess is ICCF numeric notation. In recent years, the majority of correspondence games have been played on on-line servers rather than by email or post, leading to a decline in the use of ICCF numeric notation.

PGN for computer storage

Chess games are often stored in computer files using Portable Game Notation (PGN),^[13] which uses algebraic chess notation as well as additional markings to codify a game. As mentioned, PGN requires uppercase letter O to represent castling (e.g. O-O), while the FIDE Handbook uses digit zero (0-0).

Annotation symbols

Though not technically a part of algebraic notation, the following are some common symbols frequently used by annotators to give evaluative comment on a move:

• !  an excellent move
• !!  a particularly good—and usually surprising—move
• ?  a bad move; a mistake
• ??  a blunder
• !?  an interesting move that may not be best
• ?!  a dubious move or move that may turn out to be bad
• □  the only reasonable move, or the only move available
• TN or N  a theoretical novelty

To give evaluative comment on a position:

• =  equal chances for both players
• +/=  White has a slight advantage
• =/+  Black has a slight advantage
• +/−  White has a clear advantage
• −/+  Black has a clear advantage
• +−  White has a winning advantage
• −+  Black has a winning advantage
• ∞  unclear if either side has an advantage
• =/∞  whoever is down in material has compensation for it

The symbol chosen is simply appended to the end of the move notation, for example: 1.d4 e5?! 2.dxe5 f6 3.e4! Nc6 4.Bc4+/−

See also

• Chess notation
• Descriptive chess notation

References

External links

The Wikibook Chess has a page on the topic of: Notating The Game

Look up algebraic notation or Appendix:Algebraic notation in Wiktionary, the free dictionary.

• FIDE rules on algebraic notation (see appendix C)
• Algebraic Chess Notation Exercise