Chōsokabe Yoshitoshi

Chōsokabe Yoshitoshi was the founder of the Chōsokabe clan of Tosa. At first called Hata no Yoshitoshi, he was said to descend from the Hata clan that held Sarashina district in Shinano. Chronicles relate that he fought for Retired Emperor Sutoku in the Hōgen Disturbance of 1156 and fled to Tosa after the defeat, settling in Sogabe in Nagaoka district.

Tradition makes him the builder of Okō castle and the first to bear the name Sogabe, later written Chōsokabe. His son was Toshimune.