探驪得珠 [ㄊㄢˋ ㄌㄧˊ ㄉㄜˊ ㄓㄨ; tan4 li2 de2 zhu1] to pluck a pearl from the black dragon (idiom, from Zhuangzi); fig. to pick out the salient points (from a tangled situation) to see through to the nub ◄ ►