Hidden scale and hidden color
Source: the book of the later Han Dynasty, biography of Yimin, Chen Liu's old father: "husband and dragon do not hide scales, Phoenix do not hide feathers, hang the net high, go to the safe place." Example: Ning ~, like a dragon in the abyss? Divination by Ji Kang, Wei of the Three Kingdoms
Chinese PinYin : yǐn lín cáng cǎi
Hidden scale and hidden color
If you don't get dirty, you can't do more than that. bù sè xià liú,bù zhǐ bù xíng
a bell with a wooden clapper -- used figuratively for education. jīn kǒu mù shé