Riichi Mahjong · Closed 2 / open 2

Honroutou (All Terminals and Honors) in Riichi Mahjong: Han, Examples and Odds

In riichi mahjong, Honroutou (all terminals and honors) is worth 2 han: the whole winning hand is terminals (1s and 9s) and honor tiles, with both kinds present. Calling doesn't lower it — it stays 2 han.

The rules for Honroutou

• All 14 tiles are 1s, 9s or honors — not a single 2 through 8
• It needs both suited terminals and honors: only 1s and 9s is chinroutou, only honors is tsuuiisou, and both of those are yakuman
• No chi: any sequence uses a 2 to 8. So the hand is always four triplets (toitoi) or seven pairs (chiitoitsu)
• Pon and kan are fine; open it's still 2 han

How Honroutou 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: every set needs a terminal or honor, but sequences are allowed; honroutou has none. They never stack — the game counts chanta only when there's at least one sequence.
• Toitoi and chiitoitsu: honroutou always comes with one of them.
• Sanankou, yakuhai, shousangen: with so many terminal and honor triplets, these often come along. Four concealed triplets is suuankou.
• Chinroutou and tsuuiisou: drop the honors or drop the suited tiles and it's a yakuman.

Honroutou odds

Honroutou can only use terminals and honors: 13 kinds × 4 = 52 tiles, under 40% of the 136. The chance that a random 13-tile start is entirely terminals and honors is about 1 in 760,000, so honroutou is almost always built by calling.

The more different terminals and honors you start with, the closer you are: 9 or more kinds about 0.15% of the time, 10 or more only 0.010% (the same number kokushi looks at).

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

Which hands suit Honroutou

• Lots of terminal and honor pairs: you can't finish without pons.
• A yakuhai pair: pon it for a yaku; with toitoi and honroutou it's around haneman even open.
• Terminals showing up in discards: in the middle and late game, players throw 1s, 9s and honors, so you get more pon chances. A tile with two copies already discarded can't be ponned any more.

To try it, open a table of free online riichi mahjong.

Terminals and honors in other mahjong styles

• Hong Kong mahjong's "Mixed Orphans": 1 fan (Hong Kong mahjong fan table)
• Chinese Official (Guobiao) "All Terminals and Honors": 32 fan (Guobiao fan list)

FAQ

How many han is Honroutou?

2 han, and still 2 han open. With the toitoi or chiitoitsu it always brings, it's at least 4 han.

What's the difference between honroutou and chanta?

Chanta only needs a terminal or honor in every set, and allows 1-2-3 and 7-8-9 sequences. Honroutou is terminals and honors from end to end, with no sequences.

What's the difference between honroutou and chinroutou?

Chinroutou is only suited 1s and 9s with no honors, and it's a yakuman. Honroutou includes honors and is 2 han.

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. 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. Chinroutou Yakuman A yakuman of only 1s and 9s, open or closed. Examples, the difference from honroutou, and how unlikely it is.