Light-squared bishop

A light-squared bishop is a bishop standing on a light square and, because of its movement, permanently restricted to that square color. Every diagonal step preserves color, so the bishop can never reach a dark square.

In the standard starting position, White's light-squared bishop begins on f1, the square in vertical column f and horizontal row 1, and Black's begins on c8, column c of row 8. Both players have one; “light-squared” describes the squares it can use, not the player or the physical color of the piece.

This bishop can influence only the thirty-two light squares. Its usefulness depends on which targets, pawns, and routes occupy those squares. Its own pieces may shut its diagonals, while open diagonals can let it act from one side of the board to the other. It remains a minor piece, the category formed by bishops and knights.

Promotion, which transforms a pawn when it reaches the farthest row, can also create another light-squared bishop. The color of its promotion square, the square where that transformation occurs, determines which square color the bishop can use.