脱胎换骨 — “To undergo a complete transformation”

The phrase 'Duotai Huanggu' (夺胎换骨, seizing the womb and changing the bones), closely related to 'Tuotai Huanggu' (脱胎换骨), was originally a Taoist concept. It referred to an immortal's transformation after consuming a golden elixir to shed their mortal body and replace their ordinary bones with immortal ones.

Ancient literati then borrowed the essence of these classical meanings to express their own ideas. The poet Huang Tingjian considered this a 'bone-changing method' (换骨法). He further described the process of thoroughly researching the original meaning of classical texts and elaborating on them as the 'womb-seizing method' (夺胎法).

Some also believed that by employing this 'Duotai Huanggu' technique, one could turn something ordinary into something extraordinary, much like 'turning iron into gold,' without literally copying ancient phrases word for word.