Rook pawn

A rook pawn is a pawn on the a-file or h-file. These are the two edge files, named for the rooks that begin on a1 and h1 for White, and a8 and h8 for Black. The a-pawn is traditionally the queen rook pawn and the h-pawn the king rook pawn.

Its edge location creates a simple geometric difference: while it remains on that file, it has only one capture diagonal pointing into the board. A pawn on an interior file can attack two diagonals when both squares exist. Its forward movement still follows the ordinary pawn rules.

The name does not mean that the pawn moves like a rook or belongs to one. It is part of the same system as the knight pawn, king's pawn, and queen's pawn. If it advances without capturing, its destination on the promotion rank is a corner square.