Chinese Official Mahjong · 16 pt

Pure Straight in Chinese Official Mahjong (MCR): Points, Examples and Odds

In Chinese Official Mahjong, Pure Straight (清龙) is worth 16 points: your winning hand contains 1-2-3, 4-5-6 and 7-8-9 of the same suit — a "dragon" running from one to nine. At 16 points it clears the 8-point minimum by itself.

The rules for Pure Straight

• Three chows of one suit (characters, dots or bamboo): 1-2-3, 4-5-6 and 7-8-9 — all three are needed
• The chows can be in your hand or claimed: Pure Straight does not need a concealed hand
• The fourth set can be any chow or pung, and the pair can be anything, honors included
• One section from each of the three suits (say 1-2-3 characters, 4-5-6 dots, 7-8-9 bamboo) is a Mixed Straight, worth only 8

What Pure Straight does not combine with

The three chows of the straight already contain a Short Straight (1-2-3 + 4-5-6, 4-5-6 + 7-8-9) and Two Terminal Chows (1-2-3 + 7-8-9). Under the non-repeat principle, those are not scored between the three chows of the straight.

Under the "account once" principle, the fourth chow may still combine with one of the three. If the fourth chow is 1-2-3 of dots, it forms a Mixed Double Chow (1 point) with 1-2-3 of characters; if it is 2-3-4 of characters, it forms no Pure Double Chow, Short Straight or Two Terminal Chows with any of them, so nothing is added.

Beyond that, Pure Straight excludes nothing: Concealed Hand, All Chows, Dragon Pung and Full Flush all still count.

How Pure Straight scores

The three hands below are scored live by the site's scoring engine — the same one the game uses — including the fan left out by the non-repeat rules.

Common combinations:

How it relates to other fan

• Mixed Straight: 1-2-3, 4-5-6, 7-8-9 split across the three suits, 8 points. If your straight is missing a section that another suit already has, you can fall back to it.
• Pure Shifted Chows: three chows of one suit stepping up by one or two, also 16 points and often one tile away from a straight.
• Short Straight and Two Terminal Chows: not scored between the straight's chows; the fourth chow may combine once.
• Full Flush and Half Flush: the straight already uses nine tiles of one suit, so you are halfway to a flush — stacked, it becomes a big hand.

Pure Straight odds

The site's MCR bots build toward a "target pattern" to reach 8 points, and Pure Straight is one of their routes. In 4,000 hands of normal bot play, Pure Straight appeared in 6.2% of winning hands, averaging 21.4 points (all wins average 16.3).

Far more common is the 8-point Mixed Straight, in 15% of wins: it covers one to nine too, but takes one section from each suit, so many more discards can be chowed.

When to go for Pure Straight

• Six or seven tiles of one suit, spread across 1–9: something like 1-2, 4-5, 7-8-9 — the gaps are closed or edge waits you can chow.
• You can chow: no concealed requirement, so take the missing section from the player on your left; much faster than staying closed.
• Missing edge 3 or 7: 1-2 needs the 3 and 8-9 needs the 7 — only one tile works, so chow it when you can.
• Fallbacks: if another suit has the same section, switch to Mixed Straight; with lots of one suit, Pure Shifted Chows or Full Flush.

To practise, open a table of online Chinese Official Mahjong — the points are counted for you.

Pure Straight in other mahjong styles

Japanese riichi mahjong has the same shape, called ittsu (ikkitsuukan): 2 han closed, 1 han open (see the Japanese mahjong yaku list). Taiwanese and Sichuan mahjong have no such hand.

FAQ

How many points is Pure Straight?

Pure Straight is worth 16 points in Chinese Official Mahjong — enough for the 8-point minimum on its own.

Can I chow for Pure Straight?

Yes. Claimed chows count; Pure Straight does not need a concealed hand. A concealed hand adds another 2 points.

Does Pure Straight also score Short Straight or Two Terminal Chows?

Not between its own three chows. The fourth chow can still combine once with one of them, for example as a Mixed Double Chow or Pure Double Chow.

What is the difference between Pure Straight and Mixed Straight?

Pure Straight is 1-2-3, 4-5-6, 7-8-9 of one suit, 16 points; Mixed Straight takes one section from each suit, 8 points.

How much is Pure Straight with Full Flush?

Full Flush 24 plus Pure Straight 16 is 40 points, before Concealed Hand, Self-Drawn and the rest.

Related fan

Mixed Straight 8 pt 1-2-3, 4-5-6, 7-8-9 across three suits — exactly 8 points. The most common route to a legal win: how to build it and what it stacks with. Short Straight 1 pt Two same-suit chows forming a run of six (1–6, 4–9…) for 1 point — and not counted once it becomes a Pure Straight. Two Terminal Chows 1 pt 1-2-3 plus 7-8-9 of one suit for 1 point: when it isn't counted, how account-once limits it, and its link to Outside Hand.