Nasu no Yoichi was a samurai who fought alongside the Minamoto clan in the Genpei War. He is particularly famous for his actions at the Battle of Yashima in 1185. According to the Heike Monogatari, the enemy Taira placed a fan atop a pole on one of their ships, daring the Minamoto warriors to shoot it off. Sitting atop his mount in the waves, his target atop the ship rocking as well, Nasu nevertheless shot it down with only one shot.
After the Genpei War, he was made shugo of Tottori Castle, but he lost this position to Kajiwara Kagetoki after being defeated in a hunting competition. He left Echigo Province and—following the death of Minamoto no Yoritomo—Nasu became a Buddhist monk in the Jōdo Shinshū sect. Eventually, he formed a temple, which has since been passed down to the oldest son of the Nasu family. For administrative purposes, detailed records were kept regarding who was to inherit the temple. As a result of this, it was possible to trace the Nasu lineage right up to the destruction of the temple during World War II.
Most believe that he died at the age of 64, in the year 1232, during a ceremony in Kobe honoring those who died in the Genpei War.