Riichi Mahjong · Closed 2 / open 2

Sankantsu (Three Kans) in Riichi Mahjong: Rules, Scoring and Combos

In riichi mahjong, Sankantsu (three kans) is worth 2 han: one player's hand has three kans. Closed kans, open kans from a discard and added kans all count, and it's still 2 han when open. It's rare, but when it shows up it's rarely cheap: kans carry lots of fu, and toitoi, sanankou and dora tend to come along.

The rules for Sankantsu

• You declared three kans yourself: any mix of closed, open and added kans
• 2 han open or closed
• The remaining set can be a sequence, and the pair can be anything
• If the fourth set is a kan too, it's suukantsu (yakuman) and sankantsu isn't counted

How Sankantsu is scored

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

Fu for kans (as scored on this site):

Common combinations:

The fourth kan and the four-kan draw

• A hand allows four kans at most.
• If the four kans belong to two or more players, the hand is aborted (suukaikan) once the discard after the fourth kan passes without a ron.
• If one player made all four, there's no draw: play continues and that player is on a single wait for suukantsu. Nobody else can kan any more.
• So with three kans in your hand, a fourth kan doesn't abort the hand — it's a shot at yakuman.

Why Sankantsu is rare

• Each kan needs all four copies of one tile; if a single copy ends up in another hand or a discard pile, it's impossible.
• The more kans you have, the fewer tiles you can move, so the wait is usually a single wait or a double-pair wait.
• Kans add dora for everyone, which is extra risky when someone is in riichi.

In 40,000 hands between four computers at normal level, sankantsu happened 0 times and suukantsu 0 times. Most real sankantsu hands happen on the way to toitoi or sanankou, when the fourth copy just shows up — almost nobody aims for it from the start. To get a feel for kans, play free online riichi mahjong against the computers.

Sankantsu in other mahjong styles

• Chinese Official (Guobiao), "Three Kongs": 32 fan (Guobiao fan list)
• Sichuan mahjong: no three-kong fan, but each set of four identical tiles adds 1 fan as a "root" (Sichuan Root)

FAQ

How many han is Sankantsu?

Sankantsu is 2 han, and 2 han when open — no reduction for calling.

Do open kans count for Sankantsu?

Yes. Closed, open and added kans all count, in any mix.

Does a fourth kan end the hand?

Only when the four kans are split between two or more players (suukaikan). If one player has all four, play goes on and that player is waiting for suukantsu, a yakuman.

Related yaku

Suukantsu Yakuman Four kans by one player, then a single-wait win — yakuman. Rules, the four-kan draw, combos and scoring. Rinshan kaihou Closed 1 / open 1 Win on the replacement tile after a kan — 1 han, open or closed. Rules, scoring examples, kan dora and how often it happens. 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.