Sankantsu

Sankantsu

Sankantsu (三槓子, さんかんつ) is a 2-han yaku where you have three kans (quads of four identical tiles) in your hand. The fourth meld can be anything (triplet or sequence), plus one pair. Sankantsu is very rare due to the difficulty of collecting four each of three different tiles. One more kan would upgrade to the yakuman suukantsu.

Sankantsu in detail

Requirements

To achieve sankantsu, you must have:

• Three kans: Any combination of ankan (concealed), minkan (open), or shouminkan (added kan)
• Fourth meld: Can be a triplet or sequence
• One pair: As usual

For example: 4-4-4-4 bamboo (kan), 7-7-7-7 characters (kan), South-South-South-South (kan), 5-6-7 dots (sequence), and a pair of 9-man.

Kan Types

Sankantsu accepts any kan type:

• Ankan (concealed kan): Four identical tiles from your closed hand
• Minkan (open kan): Calling another player’s discard to complete four tiles
• Shouminkan (added kan): Adding a fourth tile to an existing pon

Mixing types is common, you might have two minkan and one ankan, for instance.

Strategic Implications

Kandora Bonanza: Each kan reveals one new kandora (additional dora indicator). Three kans means three extra kandora indicators, potentially adding massive han from dora. A sankantsu hand with favorable kandora can reach mangan or higher easily.

Toitoi Likely: Since sankantsu requires three sets of four identical tiles, your hand likely includes toitoi (all triplets) unless your fourth meld is a sequence.

One Step from Yakuman: If you achieve a fourth kan, sankantsu upgrades to suukantsu (yakuman). However, in most rule sets the hand ends in an abortive draw (suukaikan) once four kans have been declared by two or more different players; only a single player making all four kans may continue toward suukantsu.

Rarity

Sankantsu is very rare because:

• Tile requirements: You need four each of three different tiles, 12 specific tiles from sets containing only four of each type
• Opponent calls: If opponents call pon or kan on tiles you need, you cannot complete sankantsu
• Draw luck: Self-drawing four identical tiles three times is statistically improbable

Kan Declaration Timing

Ankan safety: Declaring concealed kan doesn’t expose tiles to opponents but reveals new kandora (which might help others).

Minkan opportunity: Calling kan on discards speeds up completion but opens your hand and signals your strong triplet-based structure.

Four Kan Rule: If four kans are declared by two or more different players, the hand ends in an abortive draw (suukaikan) after the fourth kan’s discard settles. Be aware of other players’ kans.

Sankantsu at the table

Early in the hand, you draw four 3-bamboo tiles and declare ankan. Later, an opponent discards 8-characters when you hold three, so you call kan (minkan). You then draw four White dragons over several turns and declare ankan again. Your hand: 3-3-3-3 bamboo (ankan), 8-8-8-8 characters (minkan), White-White-White-White (ankan), plus any meld and pair. You score sankantsu (2 han) plus any other yaku. The three kandora indicators revealed might add significant additional han, pushing your hand into mangan or baiman territory.