Algebraic notation is a way to record chess games. Each square is given a specific label. Starting at White's left hand, the files are labeled from left to right with letters of the alphabet: a, b, c...to the h-file. The ranks are labeled starting closest to white, 1 through 8. Every square is therefore represented by a combination of letters and numbers: e4, f7, c3 etcetera.
Movements of pieces are recorded by using a letter to designate a piece. Queens are denoted by Q (assuming the English language is being used), rooks by R, bishops by B, knights usually by N, and kings by K. The letters must be capitalized. Pawns have no capitalization letter.
The letter of the piece, where applicable, is the first thing written in a scoring blank. There is no other label if only one piece of that type can move to a square. However, if the two black rooks were located on f8 and h2, for example, and one moved to f2, the scorer would be obligated to denote which, by writing Rf or Rh (R8 or R2 can be used as well). Sometimes the choice is made de facto if the two pieces are on the same rank or file (knights on c3 and c5, with one moving to a4: the number would be imperative).
Next comes the letter x if the move was a capture. If a pawn had been the capturing piece, the letter of their file would precede the x: ex... is a possible move in the opening. Then the square to which the piece ended its turn: exd5, Rf7, Bb5 are all possible moves.
Some moves give check: this is denoted by a plus sign after the move Qe8+. Moves giving checkmate have been shown by two plus signs ++ or a pound #. Captures en passant have e.p. written after the move. King-side castling is shown by O-O, queen-side by O-O-O.
Promoting a Pawn (in this example, to a Queen) is notated by =Q, (Q) ,or /Q. If more than one piece of the same type can move to a given square, the rank or file (or in rare cases both) of the moving piece must be given.
When scoring, the move number goes on the left hand column. White's move is given, followed by Black's in the same row. A new row begins for each move (although longer games may be read in two columns). Example:
- e4 e5
- Nf3 Nf6
When referring to a Black move, three dots precede it. Example:
A commentary might read, "2...Nf6 is Petroff's Defence".
While technically not part of algebraic notation, several symbols can be used to evaluate moves:
- !: a good move
- !!: a particularly good and usually somewhat surprising move
- ?: a bad move; a mistake.
- ??: a very bad move; a blunder
- !?: an interesting move that may not be the best
- ?!: a dubious move that is not easily refuted but may end up being bad
- Several annotations are used to represent the balance of the game (which player is more likely to win):
- =: More or less even
- +/=: Slight advantage for white
- =/+: Slight advantage for black
- +/-: Clear advantage for white
- -/+: Clear advantage for black
- +-: Winning advantage for white
- -+: Winning advantage for black
- ∞: Unclear
- =/∞: Whichever side is down in material has compensation.
- ⌓ (semicircle): Denotes a better move than the one played.
- □ (square): The only reasonable move, or the only one at all.