concealed hand; not having called any tiles
In mahjong, a hand that has not called any tiles (pon, chi, kan) from other players; all tiles are self-drawn. Often a condition for certain yaku.
from Chinese mén qián qīng
Declare riichi with a concealed hand.
This yaku requires a concealed hand.
fully concealed self-drawn win
From Chinese 門前清 (mén qián qīng), literally 'clear in front of the gate', referring to a hand that has not called any tiles.