ㄍㄨㄢguānㄒㄧㄣˋxìnˋㄒㄧˋ

  1. 觀察對方破綻等待機會行動三國演義·》:既定漢中然後練兵積粟觀釁伺隙討賊退自守。」

lit. to look for holes, and observe gaps (idiom)​, fig. to search out one's opponent's weak points, to look for the Achilles' heel