When a pawn advances to one of the six hexes at the far edge of the chess board, the player must exchange it for a piece of higher value, usually a queen. You may have more than one queen when you promote pawns. An upside down rook can serve as your second queen.

drawing of the 6-pawn board with pawn promotion shown

White pawns promote at: a10, b10, c10, d10, e9 and f8.
Black pawns promote at: a3, b2, c1, d1, e1 and f1.