# Definition:Chess/Chessboard

## Definition

A chessboard is an array (usually square) of alternating dark and light squares (conventionally referred to as black and white, even though they may well not be those actual colours).

 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

This may be referred to as an $m \times n$ chessboard, where:

$m$ is the number of ranks
$n$ is the number of files.

For the conventional chessboard, as depicted above, $m = n = 8$.

### Rank

A row of a chessboard is known as a rank.

It is identified by number:

$1$ is the rank nearest white
The ranks are numbered sequentially to the rank nearest black.

### File

A column of a chessboard is known as a file.

It is identified by letter

$\text a$ is the file on the edge of the board to the left of white (that is, to the right of black)
The files are lettered sequentially up to the file on the edge of the board to the left of black (that is, to the right of white).

### Square

The individual spaces of the chessboard are referred to as its squares.

They are conventionally identified by a letter-number pair, where:

the letter identifies its file
the number identifies its rank.