Tosa han

• Japanese: 土佐藩 (Tosa han)
• Other Names: 高知藩　(Kouchi han)
• Territory: Tosa province
• Castle: Kôchi castle
• Lords: Yamauchi clan
• Kokudaka: 200,000

Tosa was a prominent tozama and kunimochi domain located on the island of Shikoku. The 200,000 koku domain was ruled by the Yamauchi clan from Kôchi castle, its territory roughly coterminous with Tosa province.

Tosa is of particular significance in Bakumatsu and Meiji Period politics as one of the chief domains (along with Satsuma and Chôshû) from where many of the most prominent anti-bakufu shishi rebels, i.e. Imperial loyalists emerged. Prominent Tosa figures from that period include Sakamoto Ryôma, Yoshida Tôyô, Itagaki Taisuke, and Takechi Zuizan. Tosa is also significant as the domain which, while Satsuma and Chôshû were preparing for war, presented Shogun Tokugawa Yoshinobu with a petition requesting that he step down; though in the end there was some considerable fighting in the lead-up to the Meiji Restoration and its immediate aftermath, in truth, the last shogun was not forced to resign at swordpoint, but rather accepted this Tosa petition and gave up his position willingly and relatively peacefully.

Geography

Tosa is comprised of roughly the southern half of the island of Shikoku, facing the Pacific Ocean. Though not one of the designated domains for engaging in foreign interactions, as a result of its location, and the effects of the Kuroshio Current, Tosa saw a great many shipwrecks and castaways over the course of history.

Though a relatively large domain in total land area, much of this area is quite mountainous, and thus not suitable for rice cultivation; in addition to fishing and other maritime activities, much of the domain's basic agricultural production consisted of the growing of wheat, millet, beans and the like. Tea, lumber, and paper also became prominent domainal exports in the Edo period.

The domain's castle town capital was at Kôchi, located roughly midway along the domain's coast.

Edo Period

The Yamauchi were not traditionally from Shikoku, but were transferred to Tosa by Tokugawa Ieyasu in return for their loyal service, including in the Battle of Sekigahara. The Yamauchi takeover of the territory was somewhat violent, involving the forcible pacification of armed resistance by those loyal to the Chôsokabe. As a result, throughout the Edo period, even as late as the Bakumatsu, many spoke of the Yamauchi as outsiders and invaders, and those who resisted or resented Yamauchi rule often claimed associations with the Chôsokabe.

The domain's governance and laws were based, in part, however, on the "100 Article Code of the Chôsokabe," written by the Chôsokabe clan who ruled Tosa prior to the Yamauchi. Their kokudaka was based on land surveys performed by the Chôsokabe as well. Though Chôsokabe records indicate that land surveys performed in the 1590s discussed 248,3000 tan of land, an area that could produce far more than the 98,000 koku omotedaka recognized by Toyotomi Hideyoshi, in 1604, Yamauchi officials recalculated, based on the Chôsokabe reports, without actually performing a new land survey, and submitted to the Tokugawa a reported kokudaka of 202,626 koku. Only around 64% of this figure reflected rice cultivation, while the remaining portion was an estimated conversion into rice of the level of cultivation of other products, such as millet, wheat, and beans.

A particular type of Japanese long-tailed fowl called the onagadori was specially bred in Tosa, and its feathers were often used to decorate spears used in the lord's sankin kôtai processions, adding to the distinctiveness of Tosa's processions.

According to one account, Tosa was during the Edo period one of the strictest domains in terms of allowing individuals in and out of its borders, with only Satsuma, Awa, and Hizen han being identified as more tightly "closed."

Lords of Tosa

1. Yamauchi Kazutoyo (d. 1605)
2. Yamauchi Tadayoshi (1592-1664)

...

1. Yamauchi Toyoteru (d. 1848)
2. Yamauchi Toyoatsu (1825-1854)
3. Yamauchi Toyoshige (aka Yamauchi Yodo, 1827-1872)

References

• Luke Roberts, Mercantilism in a Japanese Domain: The Merchant Origins of Economic Nationalism in 18th-Century Tosa, Cambridge University Press (2002).