Riichi Mahjong · Closed 6 / open 5

Chinitsu (Full Flush) in Riichi Mahjong: Han, Examples and Odds

In riichi mahjong, Chinitsu (full flush) is worth 6 han closed and 5 han open: the whole hand — tiles in hand and every called set — comes from one suit (characters, dots or bamboo), with no honor tiles at all. On its own it already guarantees mangan or more.

The rules for Chinitsu

• All 14 tiles from one suit: all characters, all dots or all bamboo
• No honors; with honors it's honitsu instead
• Chi, pon and kan are allowed, but calling drops it one han (5 han)
• Seven pairs works too: seven pairs of one suit is chinitsu + chiitoitsu

Chinitsu vs Honitsu

Chinitsu and honitsu never stack — only chinitsu counts.

How Chinitsu waits

Tiles of one suit connect easily, so a ready hand often waits on many tiles. This one wins on every tile from 1 to 8 dots:

The downside of so many waits: you have to read them correctly yourself, or you'll miss a win or land in furiten.

How Chinitsu is scored

The yaku, han, fu and points below are computed live by the same scoring code the game uses.

Common combinations:

How it relates to other yaku

• Honitsu: one suit plus honors, 3 han closed and 2 open. If you're halfway to chinitsu but still hold an honor pair, switching to honitsu is often faster.
• Toitoi: four triplets; stacks with chinitsu.
• Ittsu, iipeikou, pinfu: with lots of same-suit sequences, these often come along.
• Chuuren poutou: the closed 1112345678999 plus one tile of the same suit — a yakuman only chinitsu can make.

Chinitsu odds

How many tiles of one suit you start with

Chinitsu needs all 14 tiles from one suit, and each suit has only 36 tiles. In a 13-tile starting hand, the strongest suit has 8 or more tiles about 1.6% of the time, and 9 or more only 0.25%.

Source: 1,000,000 random 13-tile deals.

Is it worth forcing Chinitsu?

We let computers play on this site's table: in every hand, the player with the most tiles of one suit had to go for chinitsu — discard other suits and honors first, only call that suit, no riichi, and no win without chinitsu — while the other three played normally. Then we compared the average result with the same starting hands played normally.

Source: computer play on this site. In each of 24,000 hands the seat with the best start forced Chinitsu (no riichi, no other win); the other three played normally at normal level. Points are the hand’s gain or loss, including riichi sticks.

The result isn't what you might expect: chinitsu depends on your start — with 8 or fewer tiles of one suit, forcing it loses; from 9 tiles it starts to pay.

• With 8 or more tiles of one suit, forcing it works about 14% of the time, but the average result is +392 — still below +925 for playing normally.
• With 9 or more, the success rate climbs to 23% and the average result is +1,713, beating +1,357 for normal play. Starts with 10+ are rare and the sample is small, but the gap grows.
• Finished hands averaged 6.0 han and 13,100 points, after 14.4 discards — far slower than a normal win.
• When the computers play normally, chinitsu is only 0.027% of all wins: fast play almost never stumbles into it.

Which hands suit Chinitsu

• Lots of one suit in your start: by far the most important factor — see the numbers above.
• Tiles that connect: with the same count, adjacent pairs of tiles beat scattered ones.
• Closed is worth more: 6 han closed, 5 open — one han apart. Calling is much faster, though, so weigh it against how much wall is left.
• Others will defend: two called sets of one suit and none of it in your discards give it away, and they'll hold that suit.

When to give up: someone has declared riichi and you're still far away, or the wall is half gone and you still hold several tiles from other suits. Switch to honitsu, or go back to normal play and defend. To try it yourself, open a table of free online riichi mahjong — the computers play with you and count the points for you.

Chinitsu in other mahjong styles

Full flush is a big hand everywhere, but scores differently:

• Taiwanese mahjong: 8 tai (Taiwanese mahjong Pure One Suit)
• Hong Kong mahjong: 7 fan (Hong Kong mahjong Pure One Suit)
• Sichuan mahjong: 2 fan (Sichuan mahjong Pure One Suit)
• Chinese Official (Guobiao, "Full Flush"): 24 fan (Guobiao Full Flush)

FAQ

How many han is Chinitsu?

Chinitsu is 6 han closed and 5 han open. It's mangan or more on its own.

Can Chinitsu include honor tiles?

No. With honors it's honitsu: 3 han closed, 2 han open.

Can you call for Chinitsu?

Yes, but it drops one han when open (kuisagari), to 5 han.

How many han is chinitsu chiitoitsu?

Chinitsu 6 plus chiitoitsu 2, 8 han in total — a baiman on its own.

How is Chinitsu related to Chuuren poutou?

Chuuren poutou is a special closed chinitsu shape (1112345678999 plus any tile of the same suit) and a yakuman. Every chuuren is chinitsu, but almost no chinitsu is chuuren.

Related yaku

Honitsu Closed 3 / open 2 One suit plus honors — 3 han closed, 2 open. Examples, honitsu vs chinitsu, and how many tiles you need to go for it. Chuuren poutou Yakuman（closed only） A closed 1112345678999 plus one tile — a yakuman. The 9-sided wait is junsei chuuren (double yakuman here), its link to chinitsu, and how rare it is. Toitoi Closed 2 / open 2 Four triplets and a pair, still 2 han when open. Examples, scoring combos and how many starting pairs you need.