A pawn is the most numerous piece in the game of chess, with each player starting with eight. Pawns move forward one square but capture diagonally. They can advance two squares on their first move, allowing for quicker positioning on the board. When a pawn reaches the opposite side of the board, it can be promoted to any other piece, typically a queen. This ability to transform makes pawns valuable, as they can significantly influence the game's outcome despite their initial limitations.