noun
four concealed triplets; four concealed pungs
A yakuman hand in mahjong consisting of four concealed triplets (three-of-a-kinds) and a pair, all drawn without claiming discards. The hand may be won by self-draw or, in some rules, by a discard on a single wait.
from Chinese sì àn kè
四暗刻は役満の中でも特に難しい役だ。
Four concealed triplets is one of the most difficult yakuman hands.
彼は四暗刻をツモって逆転勝利した。
He won with a self-drawn four concealed triplets and turned the game around.
A yakuman is the highest-scoring class of hands in mahjong. 四暗刻 is one specific yakuman hand.
From Chinese 四暗刻 (sì àn kè), literally 'four concealed triplets'. The reading スーアンコー reflects the Chinese-derived mahjong terminology used in Japanese.