Riichi Mahjong · Yakuman（closed only）

Chuuren Poutou (Nine Gates) in Riichi Mahjong: Yakuman Rules, Junsei Chuuren and Odds

In riichi mahjong, Chuuren poutou (nine gates) is a yakuman: a closed hand of one suit in the shape 1112345678999 plus any other tile of that suit — three 1s and three 9s, one each of 2 through 8, and the extra tile can be anything from 1 to 9.

The rules for Chuuren poutou

• One suit only (characters, dots or bamboo), no honors
• The shape is 1112345678999 + any tile of the same suit
• Closed only: no chi, pon or kan (a closed kan breaks the shape too)
• No other yaku needed — it's a yakuman on its own

Chuuren poutou vs Junsei chuuren poutou

Chuuren poutou: the winning tile isn't the extra

Before the win one tile of the shape is missing and the winning tile fills it; the extra tile is already in your hand.

Junsei chuuren poutou: the 9-sided wait

Before the win your hand is exactly 1112345678999, and any tile from 1 to 9 of that suit wins — a 9-sided wait. The winning tile becomes the extra one; this is junsei ("pure") chuuren poutou. By default this game follows Mahjong Soul and scores junsei chuuren as a double yakuman; with "Double yakuman" off in the lobby, or on Tenhou and in M-League, it's a single yakuman.

How it relates to other yaku

• Chinitsu: chuuren is always a chinitsu shape, but a yakuman isn't added to regular yaku, so only chuuren counts. Think of it as the most special chinitsu of all.
• Ittsu: 1112345678999 plus one usually also splits into 1-2-3, 4-5-6, 7-8-9, but that's absorbed by the yakuman too.
• Kokushi musou: another fixed-shape, closed-only yakuman that depends heavily on the deal.

Chuuren poutou odds

Chuuren practically never appears in this site's computer games, so here's the theory instead: the chance that 14 random tiles form exactly a chuuren shape (any suit, extra tile 1 to 9) is about one in 490 billion by exact counting (the ways to pick each of the 3 suits × 9 extra tiles, summed and divided by C(136,14)). Real chuuren hands almost always grow out of a closed chinitsu that ends up in this exact shape.

Japanese players joke that winning with nine gates uses up all your luck — that's how rare it is.

Chuuren poutou in other mahjong styles

• Hong Kong mahjong: "Nine Gates" is a limit hand (Hong Kong mahjong fan list)
• Chinese Official (Guobiao): "Nine Gates", 88 fan (Guobiao fan list)

To try it yourself, open a table of free online riichi mahjong — yakuman are scored for you too.

FAQ

Is Chuuren poutou a yakuman?

Yes. Chuuren poutou is a yakuman; the 9-sided junsei chuuren is a double yakuman by default here (you can turn that off in the lobby; Tenhou and M-League count it as single).

Can you call for Chuuren poutou?

No. It's closed only — any chi, pon or kan breaks it.

What's the difference between Junsei chuuren and Chuuren poutou?

Junsei chuuren is the hand that was exactly 1112345678999 before the win, on a 9-sided wait, with the winning tile as the extra; any other chuuren is a regular yakuman.

Related yaku

Chinitsu Closed 6 / open 5 Every tile from one suit — 6 han closed, 5 open. Examples, chinitsu vs honitsu, and how many suited tiles you need. Ittsu Closed 2 / open 1 1-2-3, 4-5-6 and 7-8-9 in one suit — 2 han closed, 1 open. Examples, waits and common combos. Kokushi musou Yakuman（closed only） One of each terminal and honor plus a pair — a yakuman. The 13-sided wait is a double yakuman here, the furiten trap, and what to do with nine terminals.