Sanankou

Sanankou
Type	Yaku
Kanji	三暗刻
English	Three concealed triplets
Value	2 han
Speed	Medium
Difficulty	Medium

Sanankou (三暗刻) is a yaku, consisting of three concealed triplets (ankou). In the case of having three triplets, the third one could not be completed with another player's discard, as this would not count as being concealed. However, if it is completed with a tsumo, then the yaku is awarded. Ankan is also counted as a closed triplet. The hand this yaku is awarded to may be open or closed, as long as it meets the conditions. This yaku is awarded 2 han.

Tile pattern cases

1. Case where the yaku is guaranteed:

Agari:

2. Case where the hand must be won by tsumo:

Tsumo:

or

3. Case where the hand is won by discard.

Ron:

or

Note: A tsumo results in the suuankou yakuman.

Formation

This yaku requires three closed triplets, as it is defined as such. As for the fourth meld, it can be either a sequence, another triplet, open, or closed.