As you sit at the chessboard, with a light square at your right and a dark square at your left, there are eight vertical rows of eight squares bordering at the sides and stretching between you and your opponent. These rows of eight squares stretch from your left to your right and cover every square of the board. These rows are called files.

File Names

Each file has a name beginning with a letter and ending with “file.” Assuming you are ready to play the White pieces, counting from your left the files are the a-file, the b-file, the c-file, and on to the file furthest to your right (the one with the light square), which is the h-file.

Files

Assuming you are ready to play the Black pieces, counting from your left the files are the h-file, the g-file, the f-file, and on to the file furthest to your right (the one with the light square), which is the a-file.

Where ranks and files intersect at a square, there is also a name. On a chessboard, find the a-file and the fifth rank. The dark square there is called a5. Now find the e-file and the fourth rank. The light square you are looking at is e4.

File Properties

Each file contains four light squares and four dark squares, which naturally alternate. Each light square borders on a dark square, and each dark square borders on a light square.

There are an equal number of light squares and dark squares on the chessboard: thirty-two for each. Place the board like a diamond and you will see them lined up in vertical and horizontal rows. These are commonly referred to as diagonals.

All files are not equal. Notice that the a-file and the h-file each border only one file, while all the other files border two files. The a-file and the h-file represent the other part of the edge of the board. (The first and eighth ranks also represent the edge of the board.)