Sen's surname has two origins.
One view is that the descendants of the Yellow Emperor, surnamed Gongsun, (Gongsun Xuanyuan, Xuanyuan Emperor. ) Shao Dianjia's son was named Jishui because he was longer than Jishui (now Qushui in huangling county, Shaanxi Province). I used to live in Xuanyuan Mountain,No. Xuanyuan. There is a bear and a bear's name in the seal. Because of advocating soil morality, the soil is yellow, so it is called the Yellow Emperor.
The great-grandson of the grandson of the Yellow Emperor made one of his sons "Senguo" a fief and became the king of Fan. Known as the Lord of Mori State, later generations follow his country's surname, Mori.
There is also a saying that Zhou Tianzi was killed, and the minister made meritorious deeds by protecting the frame, giving him a "sheng" (fief) and was later destroyed. Later generations changed their surname to "Sen".