The standard x01 game called 501 starts each player on 501 points.
Players take turns throwing up to three darts and subtracting their score from 501. The objective is to reach exactly zero, usually with the final dart landing in a double or the bullseye under double-out rules.
The “01” ending identifies the family of games that use starting numbers such as 301, 501, and 701. The odd final digit helps prevent a player from simply finishing on a round-number target without using a required finishing area. In professional steel-tip darts, 501 is the dominant format.
A leg is won by the player who completes the checkout first. If a visit takes a player below zero, leaves one when double-out is required, or reaches zero without the required finishing double, the visit is a bust and the score returns to its value before that turn. Match formats combine legs and sets in different ways.