In chess, "material" refers to the relative value of various types of pieces on the chessboard. When a series of moves and counter-moves allows one player to capture more valuable pieces than they lost, that player is said to have "gained material" while the opponent is said to have "lost material." The player with more valuable material on the board at any given time is said to have a "material advantage" over the other player. A player who purposefully loses material in order to gain compensation or a different type of advantage is said to have "sacrificed material."