Riichi Mahjong · Closed 3 / open 2

Junchan (Terminals in All Sets) in Riichi Mahjong: Han, Examples and Odds

In riichi mahjong, Junchan (junchantaiyaochuu) is worth 3 han closed and 2 han open: every one of the four sets and the pair contains a suited 1 or 9, there isn't a single honor tile, and at least one set is a sequence. It's chanta with the honors taken out.

The rules for Junchan

• Every set and the pair must include a 1 or 9: sequences 1-2-3 or 7-8-9, triplets only 1s or 9s
• No honors; with honors it drops to chanta
• At least one sequence; only 1 and 9 triplets is chinroutou, a yakuman
• Chi, pon and kan are allowed, but calling drops it one han (2 han)
• It never stacks with chanta

How Junchan waits

Like chanta, sequences can only be 1-2-3 or 7-8-9, so edge and closed waits are common. A 2-3 characters open wait takes 1 or 4, but only the 1 makes junchan. The pair also has to be 1s or 9s, so single and double-pair waits are on 1s and 9s.

How Junchan 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

• Chanta: the version with honors, 2 han closed. With junchan, chanta doesn't count.
• Sanshoku: a 1-2-3 or 7-8-9 sanshoku already fits junchan — "junchan sanshoku" is a classic big hand.
• Pinfu, iipeikou, ryanpeikou: all sequence yaku, so they combine with junchan.
• Chinroutou: only 1 and 9 triplets, a yakuman. Junchan needs at least one sequence.
• Tanyao and ittsu: the opposite shape — they never combine.

Junchan odds

In 40,000 hands where four computers played normally on this site (33,226 wins), junchan was in 0.042% of wins — even rarer than chanta at 0.25% — and those wins averaged 11,800 points.

Source: 40,000 computer hands on this site (all four at normal level), 33,226 wins. A win usually has several yaku, so the shares add up to more than 100%.

Which hands suit Junchan

• Lots of 1-2-3 and 7-8-9 shapes in your start, with few honors and few 4s, 5s and 6s.
• A visible sanshoku: junchan sanshoku is 5 han closed, a haneman.
• Closed is worth more: calling costs one han, but with sanshoku it's still 3 han open.

To practice, open a table of free online riichi mahjong and see if you can put a junchan sanshoku together.

Outside hands in other mahjong styles

• Sichuan mahjong's "quan dai yao": a 1 or 9 in every set and the pair, 2 fan (Sichuan mahjong Terminals in All Sets)
• Chinese Official (Guobiao) "Outside Hand": 4 fan, honors or not (Guobiao fan list)

FAQ

How many han is Junchan?

3 han closed and 2 han open.

What's the difference between junchan and chanta?

Honors. Chanta has honors and is 2 han closed; junchan has none and is 3 han closed. Only one of them counts.

How many han is junchan sanshoku?

Junchan plus sanshoku is 5 han closed (haneman), and it usually comes with pinfu or riichi too.

Related yaku

Chanta Closed 2 / open 1 Every set and the pair hold a terminal or honor — 2 han closed, 1 open. Chanta vs junchan, and common combos. Sanshoku Closed 2 / open 1 The same sequence in all three suits — 2 han closed, 1 open. Examples, common combos and how to spot a sanshoku chance. Chinroutou Yakuman A yakuman of only 1s and 9s, open or closed. Examples, the difference from honroutou, and how unlikely it is.