Guan Yu, also known as Yun Chang. Guan Yu is a name, the cousin of Yun Chang's Guan Yu, not a nickname.
Biozi, also known as zi, is a name given by people in the old days to express virtue or the meaning of the real name. It is an alias given by parents or teachers that is related to the meaning of the real name. In ancient times, it was inconvenient for a 20-year-old man and a 15-year-old woman to call them by their first names, so they chose another alias that was related to the meaning of their real names and called them zi to express their virtues. When ordinary people call each other respectfully, they must call them the words that express virtue, and then call the words "Piaozi".
It originated in the Shang Dynasty and became popular in the Zhou Dynasty. It later formed a system that is still used by many people in the intellectual and cultural circles until modern times, such as Hu Shizhi, Sun Wenzai, and Mao Zedong. The word Runzhi.
In modern times, except for everyone in the intellectual and cultural circles who still use it, few ordinary people use it. However, China has a population of 1.3 billion and the incidence of the same name is too high. The cultural circle is now interested in restoring expressions. According to the character system, some people who love history have the pseudonym, such as Li Haoran, Zitan, Zhou Qixing, Chengqi, and Zhang Ce, Zhuhao.
Extended information:
What is the connection in meaning between table characters and names:
The ancients were very particular about choosing table characters, and the situation is also very complicated, but upon careful inspection , analysis, and research, there are also rules to be found.
For example, it is common to choose names according to the order of eldest and youngest brothers. For example, Confucius was the second eldest, so he was named Zhongni. He also had an eldest brother, named Meng Lai. The most typical ones are the four sons of Sun Jian during the Three Kingdoms period: the eldest son, Sun Ce, was named Bofu; the second son, Sun Quan, was named Zhongmou; the third eldest son, Sun Yi, was named Shubi; the fourth eldest son, Sun Kuang, was given the courtesy name Jizuo.
There are also many cases where the word "子" is used in the word "子", because "子" was a good name or honorific for men in ancient times. So people like to use it, such as Kong Zhuang, whose courtesy name is Zisi; Zhong Yuan, whose courtesy name is Zi Lu; Sima Qian, whose courtesy name is Zichang; Cao Zhi, whose courtesy name is Zijian; Su Shi, whose courtesy name is Zizhan; Du Fu, whose courtesy name is Zimei; Yuan Mei, whose courtesy name is Zicai.
Baidu Encyclopedia-Biaozi