Algebraic notation

Algebraic notation records a game so it can be read or replayed later. Every square on the chessboard has one unique name: a letter from a through h identifies its vertical column, called a file, and a number from 1 through 8 identifies its horizontal row, called a rank. The square e4 is where the e-file and fourth rank meet.

How a move is written

The form used in game files is Standard Algebraic Notation, or SAN. A piece move combines the piece's English letter with its destination square: K means king, Q queen, R rook, B bishop, and N knight. For example, Nf3 moves a knight to f3. Pawns have no letter, so e4 means that a pawn moves to e4.

If two identical pieces can reach the same square, SAN adds information from the origin square to distinguish them. In Nbd2, the b identifies which of the two knights moves to d2.

Common symbols

• x marks a capture, as in Nxe5.
• + marks check, meaning that the king is attacked and must be made safe.
• # marks checkmate, when no legal reply can save the king.
• O-O records short castling and O-O-O records long castling. Both are forms of the special move involving the king and a rook. These are capital letters O, not zeroes.

Game files

Portable Game Notation (PGN) is a plain-text format that stores game information and moves. A PGN's move section uses SAN with English piece letters so different programs can exchange compatible files. A local publication may display other letters, but standard PGN uses K, Q, R, B, and N for pieces.