Yamagata Domain

Yamagata Domain (山形藩, Yamagata-han^?) was a feudal domain in Edo period Japan, located in Dewa Province (modern-day Yamagata Prefecture), Japan. It was centered on Yamagata Castle in what is now the city of Yamagata. Unlike some han whose control was relatively stable throughout the Edo period (1603–1867), Yamagata changed hands a great number of times during its history.

Much of Dewa Province was controlled by the powerful Mogami clan during the Sengoku period. After Toyotomi Hideyoshi assigned the Uesugi clan to Aizu, senior Uesugi retainer Naoe Kanetsugu established himself at the neighboring Yonezawa Domain, with an army of 20,000 and gradually expanded his control north into Mogami territory. However, with the help of the Date clan under Date Masamune, the Mogami were able to defend Yamagata until Naoe was forced to withdraw following the defeat of the pro-Toyotomi forces at the Battle of Sekigahara.

During the Tokugawa shogunate, in 1600, the Mogami were initially confirmed in their holdings, with an assessed income of 570,000 koku, which was the 5th largest domain in Japan at the time. However, with after the death of Mogami Yoshiaki, the clan underwent a number of inheritance struggles, and was dispossessed by the Tokugawa shogunate, and a much reduced Yamagata Domain (220,000 koku) was then assigned to the Torii clan in 1622. Torii Tadatsune died without an heir in 1636, and Yamagata was reassigned to Hoshina Masayuki (with a further reduction to 200,000 koku) until he was assigned to rule Aizu Domain in 1643.

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