Among the ancient books is Liezi, written by Lieyukou, a native of A Zheng during the Warring States Period. Later, Feng Menglong, a novelist in the Ming Dynasty, changed it into "Yu Boya Wrestling the Piano to Thank Your Companion" and included it in "Warning Records". According to legend, Yu Boya and Zhong Ziqi were in the Spring and Autumn Period, and the legend that they became bosom friends was recorded in Liezi and Lv Chunqiu, and also circulated among celebrities. It is often mentioned in China's ancient poems, such as "I'm sorry for the sorrow of the world, but the strings of Boya are silent", "The mountains and rivers are flowing, the piano is in three lanes, and a bottle of cool wine is in the moonlight" and "The child has been gone for a long time, and there is no confidant in the world". The following is a poem written by Boya after his death ("Mountains and Rivers Find a bosom friend"):
Snobbish, snobbish,
Sven, who repeats confidant?
Boya will not die in the clock,
It's amazing through the ages.
Break heptachlor, phoenix tail cold,
I'm not laughing at anyone.
All smiles are friends,
It's hard to find a bosom friend.
Think back to last spring, there was a gentleman by the river. I visited again today, but I didn't see my bosom friend. But it hurts to see a piece of land! Sad, sad, sad, can't bear to cry. Why come and go? There are dark clouds on the river bank. This song will never be played again, and the three-foot lyre will die for you!
Because of this legend, people call people who really know themselves "bosom friends", and use "high mountains and flowing water" as a metaphor for the difficulty of finding bosom friends or the beauty of music.