Section 5: Rules of Play
Rule 1.04 provides that if a player, during a throw, touches any dart already in the dartboard, that throw is deemed completed. Rule 1.05 states that a dart bouncing off or falling out of the board shall not be re-thrown, and Rule 1.06 provides that a dart falling out of the board before the throw is completed and retrieved does not count. Rule 1.07 expressly forbids a player or scorekeeper from pushing a dart into the board, or holding it in place, to stop it falling out; any dart so affected is not counted.
Starting and Finishing (Section 2): Rule 2.01 requires every match or leg to be played with a "straight start" — to begin scoring, a player need only land a dart inside the outer Doubles wire of the board. Rule 2.02 requires a "double finish" — to win a leg or match, a player must land a dart in the Double Ring or the Bull of the number equal to exactly one half of the remaining score. Rule 2.03 provides that the Bull counts as 50, and if a score of exactly 50 remains, it may be used to finish the leg or match; Rule 2.04 states the Bull counts as a "double 25" for checkout purposes.
Rule 2.09 provides that the first player to obtain the required double-out is declared the winner of that leg or match; any dart thrown by a player after finishing does not count. Rule 2.10 establishes that a match, or a set divided into legs, is played "best of" an odd number of legs (three, five, seven, etc.) — the first player to win a majority of the given number of legs is the winner, and remaining legs are not played. Rule 2.11 applies the identical majority principle to a match divided into sets.
Rule 3.01 specifies that matches or legs are played to a fixed odd number such as 501, 701, or 1001, with all scores subtracted from the total or the score remaining from the previous throw.