Why a nine-dart leg is the minimum
In the standard 501 format, each player starts at 501 and subtracts the points scored with each dart. A turn—also called an inning—allows three darts, so a player normally has up to nine throws across three turns to reach zero. The challenge is that the final dart must land in a double: the outer scoring ring, which counts twice its number, or the bull’s-eye.
The arithmetic behind the perfect finish
A classic route is to score 180 with each of the first two turns by hitting treble 20 three times. That removes 360 points, leaving 141. The last three darts can take it out with treble 20 (60), treble 19 (57), and double 12 (24). The total is exactly 501, and the last dart satisfies the double-out rule.
Other combinations can also finish in nine darts, but there is no room for a wasted throw: the player must build a huge score early and still leave a finish that can be completed in three darts.
Why it is so hard
Each dart is aimed at a small target, and the best route depends on where the previous dart lands. A slight miss can change the remaining total and force a different checkout—or make a nine-dart finish impossible. The feat is therefore more than nine accurate throws in a row: it is precise scoring followed by a carefully chosen route to zero.
