The board is positioned so that a light-colored square is in the corner to the right of both players, each of whom is provided with 16 pieces, or chessmen, of black or white color. At the start of the game eight pieces are set down in the horizontal row of squares, or rank, nearest each player. The pieces are: two rooks, or castles, in the corner squares; two knights in the adjoining squares; two bishops next to the knights; the queen on the remaining square corresponding to her color; and the king on the other remaining center square; one pawn sits immediately in front of each of these pieces. Each piece moves according to specific rules and is removed from the board when an opposing piece moves into its square, thus displacing it. The object in chess is to trap, or checkmate, the opponent's king. Students of the game use several systems of notation to describe the moves of the pieces. Over the years of modern chess history, various players have become famous for their openings, middle games, or end games, and many tactics have acquired the names of players or countries of origin, as in the Ruy Lopez opening or the Sicilian defense.