Yoshimitsu had previously studied the empty-handed martial art of "tegoi", an ancestor of the Japanese national sport of sumo, and added what he learned to the art. He eventually settled down in Kai Province (modern day Yamanashi Prefecture), and passed on what he learned within his family. Ultimately, Yoshimitsu's great-grandson Nobuyoshi adopted the surname "Takeda", which has been the name of the family to the present day. The Takeda family remained in Kai Province until the time of Takeda Shingen (武田 信玄, 1521–1573). Shingen opposed Tokugawa Ieyasu and Oda Nobunaga in their campaign to unify and control all of Japan. With the death of Shingen and his heir, Takeda Katsuyori (武田 勝頼, 1546–1582), the Takeda family relocated to the Aizu domain (an area comprising the western third of modern-day Fukushima Prefecture).