American Darts be scored for the remainder of the inning (with the exception of the center cork, which is always in play, regardless of the set "number"); the other nineteen numbers on the board are worth zero points for the remainder of the shooter's inning. So if a player throws his or her first dart at 20, in order to score the maximum possible points, but he or she misses and it lands in the 1 area, that player has established 1 as their number for their second and third darts. Thus, even if the last two darts were to land in
Darts be hit to begin scoring, known as "doubling in", with all darts thrown before hitting a double not being counted. The PDC's World Grand Prix uses this format. The minimum number of thrown darts required to complete a leg of 501 is nine. The most common nine dart finish consists of two 180 maximums followed by a 141 checkout (T20-T19-D12), but there are many other possible ways of achieving the feat. Three 167s (T20-T19-Bull) is considered a pure or perfect nine-dart finish by some players. There are a number of regional variations on the standard rules and scoring systems. "Round