also: ミンコ
noun
open three-of-a-kind (meld)
In mahjong, a set of three identical tiles formed by calling a discarded tile from another player. The meld is displayed face-up. Contrast with 暗刻 (concealed three-of-a-kind).
彼は白板をポンして明刻を作った。
He called the white dragon tile and made an open three-of-a-kind.
明刻は鳴いた牌を含むため、他のプレイヤーから見える。
An open three-of-a-kind includes a called tile, so it is visible to other players.
From Chinese 明刻 (míng kè), literally 'open engraving', used in mahjong terminology.