Why Is Darts 501? The History and Strategy Behind the Most Popular Format

The Double-Out Rule Changes Everything

To win a leg of 501, you must reach exactly zero, and your very last dart must land in the outer ring (a double) or the bullseye (which counts as double 25). This is called double-out. You cannot simply throw three treble 20s and call it a day — the final dart must hit a double, and your score before that dart must be an even number.

This rule is the key to understanding why 501 exists. Because you must finish on a double, you need to reach an even number before your checkout dart. An odd starting number like 501 forces you to break parity — you must score an odd number of points at some point to turn 501 (odd) into an even number from which you can finish. If the game started at 500 (even), you could theoretically go 20, 20, 20 every turn, reach zero, and never touch any other part of the board.

The bullseye (inner bull) is a valid double because it sits in the double ring — it is double 25. This is why so many professional checkouts end on bullseye: it is the highest-value double on the board and often the most forgiving path when treble accuracy wavers under pressure.

Why an Odd Number? The Board Movement Argument

Imagine a game that started at 500. A player could throw three single 20s for 60 points, turn after turn, and eventually reach zero. The game would be boring, predictable, and require almost no strategy. The only variation would come from missed darts. That is not a compelling spectator sport.

Starting at 501 (an odd number) changes everything. After one turn of three single 20s (60 points), the score goes from 501 to 441. Still odd. After another 60, it is 381. Still odd. The player must eventually deviate from the 20 segment to score an odd number of points in a turn, breaking the parity and reaching an even number that allows a checkout attempt.

This forces players to use segments like 19, 17, 15, and the bullseye creatively. A player on 321 might throw treble 19 to reach 264, then treble 20 to reach 204, setting up a more favourable checkout. The odd starting number introduces a layer of arithmetic and route planning that would not exist with an even start. Every leg becomes a puzzle as much as a throwing contest.

The History: From Cribbage Boards to the PDC

The Cribbage Board Era

The original "01" game was 301, not 501. In the early 20th century, English pub players scored darts on cribbage boards. A cribbage board has tracks of 121 holes, so two trips around the board scored 242 points — close to the 301 that became the informal standard. Scoring was tracked with pegs, just like in the card game cribbage, which is where the phrase "peg your score" in darts comes from.

As players became more accurate through the mid-1900s, 301 started feeling too short. A skilled player could finish a leg in six or seven turns, barely giving opponents room to recover from a bad throw. Tournament organisers wanted a format that balanced excitement with fairness. They experimented with longer formats, and 501 emerged as the sweet spot — long enough to test consistency and allow comebacks, short enough to keep matches within a broadcast-friendly duration.

501 Becomes the Professional Standard

By the time the British Darts Organisation (BDO) formed in the 1970s and the Professional Darts Corporation (PDC) split off in the 1990s, 501 was firmly established as the standard format for professional play. Both organisations adopted it for their major tournaments, and the Dartsva platform follows the same format so your practice translates directly to competitive play.

Variants like 701 and 1001 exist, mostly in soft-tip darts and team formats. These extend the game length for more players or to compensate for the larger soft-tip target areas. But 501 remains the gold standard — the distance that defines professional darts.

Setup Shots: The Chess Match Within 501

Experienced 501 players do not just throw at treble 20 and hope for the best. Every turn from about 250 downwards involves setup strategy. A setup shot is a scoring combination designed to leave a preferred checkout rather than the maximum possible score. This is where 501 reveals its depth.

Consider a score of 126 with three darts in hand. An inexperienced player throws at treble 20 and lands 60, leaving 66. Now they need treble 10, double 18 — an awkward path. An experienced player goes treble 19 first. If they hit it (57), they have 69 left. A single 19 leaves 107, still workable. Two treble 19s give 114, leaving double 6 — a comfortable finish. The route is safer because a miss into the 3 segment (adjacent to 19) still leaves a manageable score, whereas a missed 20 into the 1 or 5 can be devastating.

Dartsva's Gauntlet assessment evaluates your checkout choices and shows you where your setup strategy needs work. Many amateur players lose legs not because they cannot hit doubles, but because they leave themselves on awkward numbers — the very problem 501 is designed to expose.

Here are some common setup numbers that every 501 player should know:

• 170: Maximum checkout. Treble 20, treble 20, bullseye. Also called a big fish.
• 167: Treble 20, treble 19, bullseye. The alternative when 20s are blocked.
• 110: Treble 20, bullseye. A common two-dart finish.
• 100: Treble 20, double 20. Clean and direct.
• 32: Double 16. The most common checkout in darts — two single 16s, then double 16.
• 40: Double 20. A popular checkout because the 20 segment is where your eye is already trained.

Why 501 Instead of 301 or Cricket?

301: Too Short for Fair Competition

301 was the original O1 game, and you still see it in casual pub play. But at a competitive level, 301 is too short. A professional player can average 100+ points per turn, meaning they can finish a leg of 301 in as few as four turns (12 darts). The margin for error is tiny. One bad turn and the leg is effectively over — you have no time to recover.

501 gives players roughly eight to fifteen turns per leg at the professional level. That extra length means comebacks are possible. A player who scores 140, 100, 41 in their first three turns is on pace for a 15-dart leg. Their opponent, who might have started with 60, 45, 60, is behind but not out of the leg. The extra distance allows the scoring to average out and the better checkout player to win — which is exactly what makes darts compelling to watch.

Cricket: Fun but Not a Precision Test

Cricket is a popular alternative in American bar play, but it has not replaced 501 as the competitive standard. Cricket limits the board to seven targets (20 through 15 and bullseye), which reduces the strategic surface area of the game. A Cricket game between two skilled players can also drag on indefinitely if both keep scoring points, making it impractical for tournament scheduling.

501, by contrast, has a guaranteed endpoint. Someone reaches zero and the leg stops. That certainty, combined with the full-board movement, makes 501 the format that best separates skill from luck over a short sample of throws. That is why every PDC world championship, every Premier League night, and every major tournament uses 501.

The Nine-Darter: Perfection in 501

The nine-dart finish — completing 501 in exactly nine darts — is the holy grail of darts. It requires eight trebles and a double, or seven trebles and two doubles (depending on the route). The most common path is treble 20, treble 20, treble 20 (180); treble 20, treble 20, treble 20 (180); and treble 20, treble 19, double 12 (141 checkout).

The nine-darter only exists because 501 is the format. With 301, the perfect game would be a six-darter, which lacks the drama and difficulty of sustaining perfection across two full turns. With 701, the nine-darter would not be possible at all — you would need more than nine darts. The number 501 sits in a sweet spot where nine darts is theoretically achievable but practically so difficult that it remains a career-defining achievement for every player who lands one.

On Dartsva, you can track your 180 rate and checkout percentage over time. While a nine-darter may be years of practice away for most players, seeing incremental improvement in your scoring phases is the path that leads there.

Why Not 500 or 510? The Parity Problem

A common question is why the sport settled on 501 rather than any other nearby number. The answer comes down to parity and the double-out rule. Any even starting number would allow a player to throw only even-scoring combinations (like single 20, which scores 20, which is even) and eventually reach zero without ever touching another segment.

An odd starting number guarantees that the player must, at some point, score an odd number of points in a turn to reach an even checkout position. This forces deviation from the 20 segment. Numbers like 501, 301, 701, and 1001 all serve this same purpose — they are all odd. The specific choice of 501 over 301 was a historical decision based on game length, but the oddness is a mathematical necessity that defines the entire O1 family of games.

Why not 401 or 601? 501 simply emerged as the standard length through decades of tournament play. It is short enough for broadcast but long enough for skill to determine the outcome. Like the distance of a marathon or the length of a tennis set, 501 is not inherently special — it is the number that competitive evolution settled on.

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