Yamagata Domain (山形藩 Yamagata-han?) was a Japanese fief (han), located in Dewa province, in the Tōhoku region (north-eastern Honshū). Modern-day Yamagata Prefecture is roughly contiguous with the domain, and its capital city, also called Yamagata, grew up out of the daimyo's (feudal lord's) castle town. Unlike some han whose control was relatively stable throughout the Edo period (1603-1867), Yamagata changed hands a great number of times within a very short space of time.
In the Sengoku (1467-1603) and Edo periods, the territory changed hands a number of times, and came to play an important role in the battles immediately leading up to the Sekigahara Campaign of 1600. At the time, Yamagata was controlled by Mogami Yoshiaki who had taken it from the Uesugi family. Along with a number of allies, he defended the domain from the army of Naoe Kanetsugu, an ally of Ishida Mitsunari, who made his way towards Yamagata from the neighboring Yonezawa Domain, with an army of 20,000. Ultimately, though Mogami and others engaged Naoe's forces a number of times, no battle was fought at Yamagata Castle. With the help of Date Masamune, Naoe's armies were held off until news of Ishida Mitsunari's defeat by Tokugawa Ieyasu at Sekigahara was heard, and Naoe withdrew.
Following Sekigahara, Yamagata was formally established as a han by the Tokugawa shogunate, and assigned to the Mogami clan along with an income of 570,000 koku. However, it was reassigned to the Torii family of samurai in 1622, with an income of 220,000 koku. They held it but briefly; in 1636, the domain reverted to the control of the shogunate, due to the lack of a Torii heir. The Okudaira and Matsudaira families, branches of the shogunal Tokugawa clan, would control Yamagata intermittently from then on, in between other daimyo families.
Some time later, Yamagata's lord Okudaira Tadamasa died, many of his retainers and would-be heirs committed junshi, killing themselves in order to loyally follow their lord into death. Thus, the han fell to Hotta Masanaka. However, Masanaka's father, Hotta Masatoshi, killed someone inside the shogun's capital of Edo castle, and thus had his family's lands seized.
The line of lords of Yamagata
- Period as tenryō, 1764-1767
- Genealogy of the lords of Yamagata (Japanese)
- Turnbull, Stephen (1998). 'The Samurai Sourcebook'. London: Cassell & Co.