also: かわ
noun
discarded tiles; discards
In mahjong, refers to the pool of tiles that players have discarded during play. The term is borrowed from Chinese hé.
from Chinese hé
彼は河から安全牌を拾った。
He picked a safe tile from the discards.
河を見て相手の待ちを読む。
Read the opponent's wait by looking at the discards.