This diagram shows the layout of a standard dart board. In a standard game of darts each player has three darts, which they take turns to throw at the board. Players begin with a score, usually 501, which they reduce down to zero through scoring points on the darts board. The board is divided into 20 radial sections, each marked with a score. If the dart lands on a double ring or a triple ring, the score is doubled or tripled respectively. A dart in the 'outer bull' (also called the 'outer' or 'iris') scores 25; on the 'bullseye' ('bull' or 'inner bull') it scores 50. The final dart of the game is usually supposed to land either on the bullseye or on a double. In some games a double must be hit to start scoring. This is known as a 'double in' game.