Square

A square is the basic unit of the chessboard. It may be empty or occupied by one piece. Its name combines the letter of its file, a through h, with the number of its rank, 1 through 8. The square e4, for example, lies on the e-file and the fourth rank.

The name is unique and permanent: e4 remains e4 no matter which side is viewing the board. This reference system makes it possible to describe positions and record moves. In algebraic notation, the standard system for writing moves, a pawn move may be shown using only its destination square, such as e4.

There are 32 light squares and 32 dark squares. Squares on the same diagonal share a color, so a bishop that begins on a light square can never reach a dark one, and vice versa. A square's classification also stays the same when a board design uses colors other than literal white and black.