The Nanbu clan sided with
Tokugawa Ieyasu's Eastern Army during the
Battle of Sekigahara. In the wake of Ieyasu's victory, the Nanbu clan was confirmed in its lordship of (also known as the ). The
kokudaka of the domain was officially 100,000
koku, but later in the Edo era, was doubled in amount. The Nanbu clan retained its holdings for the entirety of the
Edo period, surviving until the
Meiji Restoration. During the Edo period, two new branches of the Nanbu clan were founded, one at
Hachinohe, and the other one at
Shichinohe. In 1821, the old tensions between the Nanbu and Tsugaru flared once more, The Nanbu clan's territories were also among those effected by the
Tenpō famine of the mid-1830s. As with many other domains of northern Honshū, the Morioka Domain was assigned by the shogunate to policing portions of the frontier region of
Ezochi (now
Hokkaido). The clan's first direct encounter with foreigners came in the late 16th century, when a Dutch ship, the
Breskens, arrived in Nanbu territory. A shore party from the ship was captured by local authorities and taken to
Edo. Over the course of its history particularly in the Edo period, there were several retainers of the Nanbu clan who became famous on a national scale. Narayama Sado, a clan elder (
karō) who was active during the
Boshin War, was one of them; he was responsible for leading the Nanbu clan's political activity and interaction with neighboring domains.
Hara Takashi, who later became Prime Minister of Japan, was another. Some 20th-century figures in Japanese politics also came from families of former Nanbu retainers; perhaps the most well known of which was
Seishirō Itagaki and
Hideki Tōjō.
Boshin War During the
Boshin War of 1868–69, the Nanbu clan initially attempted to remain neutral. However, under the leadership of
Nanbu Toshihisa and the
karō Narayama Sado, the Nanbu clan later sided with the
Ōuetsu Reppan Dōmei). By October 7, Nanbu troops took
Ōdate, one of the Akita Domain's castles. However, due to the collapse of the alliance, the Nanbu clan surrendered to the imperial army on October 29, 1868. After the war, the Nanbu clan's holdings were drastically reduced by the imperial government as punishment for siding with the northern alliance. While Hachinohe and Shichinohe Domains survived intact, a large area of what is now northeastern Aomori Prefecture was given as a resettlement zone for former samurai of
Aizu Domain. The Nanbu were also briefly expelled from Morioka itself, and were assigned new lands surrounding the vacant
Shiroishi Castle before being allowed to return to Morioka a few months later. Two years after the war, as with all other
daimyō, the heads of all three Nanbu branches were relieved of their offices by the
abolition of the han system. ==Meiji era and beyond==