file a letter

Thus each square has a unique identification of file letter followed by rank number.

If instead an inner Rook is associated with that right, the traditional castling tag will be replaced by the file letter of the involved Rook, using upper case for White.

Thus, each square is identified by its file letter and rank number.

AMBIGUITY - If more than one piece of the same type can move to a square, the rank number or file letter of the origination square is added.

Each square of the board, then, is uniquely identified by its file letter and rank number.

The New York Times has converted its method of chessboard notation to the algebraic system, in which each square is unambiguously identified by file letter and rank number.

A square on the queenside is designated by its file letter and then its rank letter.

In a few cases a more detailed representation is needed to resolve ambiguity; if so, the piece's file letter, numerical rank, or the exact square is inserted after the moving piece's name (in that order of preference).