It is said that in the clan of the Duke of Jin during the Spring and Autumn Period there was one called Bi Wan, or Han Wan, who was the younger brother of Earl Zhuang of Quwo. Bi Wan was conferred in Hanyuan, from which his offspring took the surname Han. Bi Wan (Han Wan) and his descendents were almost all senior officials of state Jin.

Later, state Han become one of the seven powers during the Warring States Period with its capital in Pingyang. As the Han's territory expanded it moved its capital to today's Henan. Therefore the surname Han spread from Shanxi to today's Shaanxi and Henan, and eventually to the whole country.

After state Qin unified the other six states the royal descendents of state Han adopted the surname Han. According to historical records many ethnic groups in China changed their compound surnames to single-character surnames, and several adopted Han because of similar pronunciation.

Also there are recordings of some Koreans with the surname Han during the reign of Emperor Wu of the Han Dynasty and a Japanese called Han Zhihe during the reign of Emperor Xian of the Tang Dynasty, which indicate the blending of foreign surname Han. The surname Han has three sources. The main one, however, came from Chinese surname Han.

By People's Daily Online