If a player advances a pawn to its eighth (final) rank, the pawn is then immediately promoted (converted) to a queen, rook, bishop, or knight of the same color at the choice of the player (a queen is usually chosen). The choice is not limited to previously captured pieces. Hence it is possible for a player to have for example multiple queens in play at once. If players don't have the extra game pieces available then the promoted piece should be marked so that both players know which game piece it is.