The rules of 501, 301, Around the World and Bob’s 27

How each game is actually scored: double out, the three ways to bust, what a leg is, and the two practice routines worth doing — round the board and Bob’s 27.

Darts has more variants than it has players with strong opinions, which is saying something. These are the rules the app plays by, written out because "double out" hides more detail than it looks like it does.

501 and 301

You start on 501 (or 301, for a shorter game) and subtract what you throw. Three darts a turn. The first player to reach exactly zero wins the leg — and the dart that takes you there has to be a double.

Ending on a double is the whole game. It is why 40 is a comfortable finish and 41 is not, and why players talk about leaving themselves an even number.

The three ways to bust

A turn busts, and your score goes back to what it was when the turn started — not just before the offending dart — if any of these happen:

• You go below zero.
• You land on exactly 1, because there is no double of anything that leaves 1 finishable.
• You reach zero with a dart that is not a double.

Rewinding the whole turn is the part people get wrong. Throw 60 and 60 from 121 and then a single 1, and you are back on 121, not on 1.

Double in

An optional extra: nothing counts until you have hit a double to open. It makes a leg considerably longer and is off by default.

Legs and sets

A match can be a single leg or a best of three, five or seven. Scores reset each leg; the legs won do not, and the throw alternates every leg.

Stack sets on top and you have the World Championship shape: each set is its own best of legs, and the match goes to whoever takes the sets. A set starts level — both scores and both leg counts come back — and the set opener alternates too, so both players open the same number of sets however long each one runs.

Who throws first is thrown for: one dart each at the bull, closest opens. Everything after that alternates off it.

Around the World

A practice game rather than a match: hit 1, then 2, then 3, all the way to 20, then the bull. Any ring of the number counts — a single, a double or a treble all advance you — and for the bull both 25 and 50 count. Fewest darts wins.

The two drill versions are the same ladder with the bar raised: only doubles count, or only trebles. Round the board on doubles is the single most useful practice routine in darts, because doubles are what actually lose you legs.

Bob’s 27

A doubles drill with a score and a way to fail, which is what makes it stick. You start on 27 and throw three darts at every double in turn, D1 through D20 and then the bull.

• Each dart that hits the target double adds twice its value.
• A round in which you miss all three subtracts twice the value.
• Drop below 1 and the run is over.

Surviving all 21 rounds is a good session. The early doubles are worth almost nothing and cost almost nothing; the run is usually decided in the teens.