Algebraic notation (chess)

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:), but using it is not allowed by FIDE rules.

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 any indication that a 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), but such description is not allowed by FIDE rules. These shortened forms are sometimes called minimal or abbreviated algebraic notation.

	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

1.Bdb8, 2.Rdf8, 3.R1a3, 4.Qh4e1

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 of departure (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, in the diagram, Bb8 would be ambiguous, as either of the bishops on a7 and d6 could legally move to b8. The move of the d6 bishop is therefore specified as Bdb8, indicating that it was the bishop on the d file which moved. Although they could also be differentiated by their ranks, the file letter takes precedence.

For the black rooks both on the 8th rank, both could potentially move to f8, so the move of the d8 rook to f8 is disambiguated as Rdf8. For the white rooks both on the a file which could both move to a3, it is necessary to provide the rank of the moving piece, i.e., R1a3.

In the case of the white queen on h4 moving to e1, neither the rank nor file alone are sufficient to disambiguate from the other white queens. As such, this move is written Qh4e1.

As above, an "x" can be inserted to indicate a capture; for example, if the final case were a capture, it would be written as Qh4xe1.

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.

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

While the FIDE Handbook, appendix C.13[5] uses the digit zero (0-0 and 0-0-0), PGN requires the uppercase letter O (O-O and O-O-O).[6]

A move that places the opponent's king in check usually has the symbol "+" appended. Alternatively, sometimes a dagger (†) or the abbreviation "ch" is used. Double check is commonly indicated the same as check, but is sometimes represented specially as "dbl ch", or in older books as "++". Some publications indicate a discovered check with an abbreviation such as "dis ch". 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 "# ".) The word mate is commonly used instead. Occasionally the double dagger (‡) is seen. A checkmate is represented by "≠" (the not equal sign) in the macOS chess application. In Russia and ex-USSR, where captures are indicated by ":", checkmate can also be represented by "X", "x", or "×".

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. In case of forfeit, scores 0–0, ½–0 and 0–½ are also possible. If player(s) lost by default, results are +/−, −/+ or −/−.

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 or forfeit. (Similarly, there is more than one way for a game to end in a draw.) Sometimes direct information is given by the words "White resigns" or "Black resigns", though this is not considered part of the notation but rather a return to the surrounding narrative text.

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 unlabeled, just like in regular algebraic notation.) 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.[14]

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. Sometimes it is separated by a hyphen (contrary to FIDE rules), for example: e2e4 or Nb1-c3 with hyphen. 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 piece names) 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).

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.