Origins of the Yu (于) surname
Chinese sources record 7 separate lines of origin for the Yu (于) surname. Each is summarised below with its source.
Originated from the Zi (子) surname
During the late Shang Dynasty, a son of King Wu Ding of Shang was enfeoffed as the Marquis of Yu (Yu Hou 于侯), with his fief located in the northwest of today's Qinxian County (沁县), Henan Province; after the state was destroyed, his descendants adopted the state's name as their surname.
Originated from the Ji (姬) surname
Yu Shu (邘叔), the second son of King Wu of Zhou (周武王), was enfeoffed in the State of Yu (邘国); his descendants removed the 'city' radical (邑) from the character for Yu (邘), simplifying the state’s name to form the Yu (于) surname.
Originated from the Chunyu (淳于) clan
During the reign of Emperor Xianzong of the Tang dynasty, the Chunyu (淳于) clan changed to the single-surname Yu (于) clan to avoid using the character 'chun' (纯) due to naming taboos.
Originated from the Xianbei Wan-niu-yu (万忸于) clan
During the sinicization reforms implemented by Emperor Xiaowen of the Northern Wei dynasty, people of the Central Plains who had previously changed their surname to Wan-niu-yu (万忸于) restored their original surname Yu (于).
Originated from the Xianyu (鲜于) clan of the Dingling (丁零)
After Emperor Xiaowen of the Northern Wei (北魏) carried out Sinicization reforms, some members of the Xianyu (鲜于) clan changed their surname to Yu (于).
Originated from the Manchu Nimaha (尼玛哈) clan
The Manchu Nimaha (尼玛哈) clan changed their surname to Yu (于) or Yu (於), homophonous surnames, because 'Nimaha' means 'fish'.
Originated from the Yuan-dynasty (元朝) Bayan (巴延) clan
During the Ming dynasty (明朝), Bayan Darī (巴延达哩) of the Yuan dynasty was granted the surname Yū (於) and personal name Zhōng (忠), an example of imperial bestowal of the Yū (於) surname.