爐火純青 [ㄌㄨˊ ㄏㄨㄛˇ ㄔㄨㄣˊ ㄑㄧㄥ; lu2 huo3 chun2 qing1] lit. the stove fire has turned bright green (allusion to Daoist alchemy) (idiom) fig. (of an art, a technique etc) brought to the point of perfection ◄ ►
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