Chu Jiu's friendship comes from the Book of the Later Han Dynasty. Wu has a biography. At that time, Shamu, a public servant, came to visit imperial academy. He had no money, but he became a guest servant in order to rent money. Yu Yu was frightened and decided to give it to Chu Jiu. " It means not to be too poor to make friends.

In the Eastern Han Dynasty, there was a poor and studious scholar named Gong Shamu. After a period of hard study, I always thought that my study was limited and I wanted to enter Beijing Imperial College for further study. Gong Shamu's family is poor and doesn't have much money for him to study in imperial academy. So Gong Shamu went to a rich family in Wu You to make a husker. Wu You served as Qi Xiang, Chang Shi and other official positions. One day, when Gong Shamu was in Xi Valley, Wu You came to see him. Wu You saw that Gong Shamu was polite and not like a clown at all, so he began to strike up a conversation with him. During the conversation, You Wu found Gong Shamu knowledgeable and original. Wu You became friends with him before Chu Jiu, regardless of the disparity between the rich and the poor. In feudal society, rich and poor counties were different and hierarchical. It is rare for a rich man to condescend to make friends with a poor scholar, so it is passed down as a much-told story.