鲜为人知

xiǎn wéi rén zhī

little known

Character by character

鲜xiǎn
rarely

为wéi
by

人rén
people

知zhī
known

这本书讲了很多鲜为人知的历史故事。

The book tells many little-known stories from history.

Tone: neutral.

Tone trap: 鲜 is xiǎn (rare), 为 is wéi (by). Opposite: 众所周知.

Learn it in context

This idiom and thousands more are in Learn Chinese with Bao, with audio, pinyin and drills that make them stick.