how to play shanghai darts

Subsidiary rules of shanghai darts: Single/double bullseye is optional.

One game of seven rounds, in order to throw 1-20 each score area and bullseye, hit the target area to score the corresponding points (for example, if you hit 5 points of the target score area of three times the area, you score 5 × 3 = 15 points), hit the non-target area is invalid (score 0 points). One dart hit in each scoring area will be transferred to the next scoring area. If a player hits three darts in a round with three different target zones (i.e. one dart each for single, double and triple), that player wins the shanghai  dart game. If no player wins by the above method after seven rounds, the player with the highest score wins in shanghai darts rules.