“The Chōsokabe family, unlike many other contemporary sengoku daimyō, traced its pedigree to at least 1180 which was before the founding of the Kamakura bakufu. The family became a contender for the local hegemony in shikoku during the Ōnin War, when the Hosokawa who held the hereditary position of shugo could no longer provide adequate local attention.

Chōsokabe Motochika (1538–1599) succeeded to the family leadership (katoku) in 1560. Starting in 1570 he began a series of military campaigns which culminated in the battle of 1583 against the Kawano, which enabled him to become the lord of the entire Shikoku. However, he fought against Toyotomi Hideyoshi and was defeated by the latter in his Shikoku campaign. Thereafter he swore fealty to Hideyoshi and received the latter’s assurance that he could keep Tosa in the southern part of Shikoku as his domain.

He fought for Hideyoshi in the two Korean campaigns which was disastrous for the economic well-being of his domain. After his death the family sided with Hideyoshi’s heir against Tokugawa Ieyasu, and the last of the Chōsokabe was executed after the defeat in the battle of the Osaka castle which took place in 1615. Among the major accomplishments of Chōsokabe Motochika was his cadastral survey which was begun in 1587 and completed in 1598. The survey identified those farmers–who were separated from military duties–and who were responsible for the payment of a set amount of taxes.”

The ancient capital of the former province Tosa (today’s Kochi prefecture on the island of Shikoku) was near the modern city of Nankoku. Even under the Chōsokabe, Tosa remained a relatively poor province and lacked a strong castle town.

The Chōsokabe family crest, drawn from
a copy displayed at the Samurai Archives:



Sources:
Quote from Japan: A Documentary History by David John Lu
Wikipedia
Wikimedia Commons
The Samurai Archives