Dewa Province in the context of "Battle of Ōshū"

Mutsu Province (陸奥国, Mutsu no Kuni; Japanese pronunciation: [mɯꜜ.tsɯ (no kɯ.ɲi)]) was an old province of Japan in the area of Fukushima, Miyagi, Iwate and Aomori Prefectures and the municipalities of Kazuno and Kosaka in Akita Prefecture.

Mutsu Province is also known as Ōshū (奥州) or Michinoku (陸奥 or 道奥). The term Ōu (奥羽) is often used to refer to the combined area of Mutsu and the neighboring province Dewa, which together make up the entire Tōhoku region.

Akita Prefecture (秋田県, Akita-ken; Japanese pronunciation: [aꜜ.kʲi̥.ta, a.kʲi̥.taꜜ.keɴ]) is a prefecture of Japan located in the Tōhoku region of Honshu. Its population is estimated 915,691 as of 1 August 2023 and its geographic area is 11,637 km (4,493 sq mi). Akita Prefecture is bordered by Aomori Prefecture to the north, Iwate Prefecture to the east, Miyagi Prefecture to the southeast, and Yamagata Prefecture to the south.

Akita is the capital and largest city of Akita Prefecture. Other major cities include Yokote, Daisen, and Yurihonjō. Akita Prefecture is located on the coast of the Sea of Japan and extends east to the Ōu Mountains, the longest mountain range in Japan, at the border with Iwate Prefecture. Akita Prefecture formed the northern half of the historic Dewa Province with Yamagata Prefecture.

Yamagata Prefecture (山形県, Yamagata-ken) is a prefecture of Japan located in the Tōhoku region of Honshu. It has a population of 1,005,926 (1 February 2025) and an area of 9,325 km (3,600 sq mi). Its neighbours are Akita Prefecture to the north, Miyagi Prefecture to the east, Fukushima Prefecture to the south, and Niigata Prefecture to the southwest.

The capital and largest city is Yamagata, with other major cities being Tsuruoka, Sakata and Yonezawa. The prefecture is located on Japan's western Sea of Japan coast and its borders with neighboring prefectures are formed by various mountain ranges, with 17% of its total land area being designated as Natural Parks. Yamagata Prefecture formed the southern half of the historic Dewa Province with Akita Prefecture and is home to the Three Mountains of Dewa, which includes the Haguro Five-story Pagoda, a recognised National Treasure of Japan.

The Three Mountains of Dewa (出羽三山, Dewa Sanzan) refer to the three sacred mountains of Mount Haguro, Mount Gassan and Mount Yudono, which are clustered together in the ancient province of Dewa (modern-day Yamagata Prefecture). Holy to the Japanese Shinto religion and especially the mountain ascetic cult of Shugendo, Dewa Sanzan are a popular pilgrimage site visited by many, including famed haiku poet Matsuo Bashō.

The Haguro Five-story Pagoda is a recognised national treasure of Japan.

The Satake clan (佐竹氏, Satake-shi) was a Japanese samurai clan that claimed descent from the Minamoto clan. Its first power base was in Hitachi Province. The clan was subdued by Minamoto no Yoritomo in the late 12th century, but later entered Yoritomo's service as vassals. In the Muromachi period, the Satake served as Governor (shugo) of Hitachi Province (today Ibaraki Prefecture), under the aegis of the Ashikaga shogunate. The clan sided with the Western Army during the Battle of Sekigahara, and was punished by Tokugawa Ieyasu, who moved it to a smaller territory in northern Dewa Province (northern Honshū) at the start of the Edo period. The Satake survived as lords (daimyō) of the Kubota Domain (also known as the Akita Domain). Over the course of the Edo period, two major branches of the Satake clan were established, one ruled the fief of Iwasaki, the other one the fief of Kubota-Shinden.

During the Boshin War of 1868–69, the Satake were signatories to the pact that formed the Ōuetsu Reppan Dōmei, but after internal debate and a disagreement with the Sendai Domain, the clan switched sides and joined the imperial forces in subduing the alliance. As with all other daimyō families, the Satake clan was relieved of its title in 1871.