The Yamanouchi or Yamauchi (Japanese 山内氏, Yama(no)uchi-shi) were a family of the Japanese sword nobility (Buke) derived from Fujiwara no Hidesato.
With an income of 242,000 koku, the Yamanouchi residing in Kōchi (Kōchi Prefecture) were among the great Tozama-Daimyō of the Edo period.
Members of the family Yamauchi
Toshimichi (俊道), Hidesato's 10th generation descendant, was the first to take the Yamanouchi name.
Moritoyo (盛豊) held the castles of Iwakura and Kuroda in Owari province in the 16th century.
Kazutoyo (一豊, 1546-1605), Moritoyo's son, began his service with Oda Nobunaga at the age of 13. Toyotomi Hideyoshi gave him the fief of Takahama in Wakasa province in 1582, Nagahama Castle in Ōmi in 1585, and the title of Tsushima no kami. In 1590, he was transferred to Kakegawa (Tōtōmi) with an income of 50,000 koku. He then joined Tokugawa Ieyasu, who gave him the province of Tosa with 242,000 koku in 1600 after the Battle of Sekigahara.
Yōdō (容堂, 1827-1872), or Toyoshige (豊信), took a leading role in the overthrow of the shogunate. He was the first to write to the shogun at the suggestion of Gotō Shōjirō (1838-1897) to resign and return the country to the Tennō. Yōdō held various offices in the new government after the Meiji Restoration. The family then held the title of Tosa no kami.
Yamauchi Clan Branch lines
Two branch lines existed, which after 1868 were given the title (Kazoku) vice count and baron, respectively.