The Battle of Ōshū (奥州合戦, Ōshū-kassen) was a major battle between the Kamakura government and the Northern Fujiwara that took place in the Tōhoku region of Japan from September 1 to October 14, 1189. It resulted in the downfall of the Northern Fujiwara and the completion of Minamoto no Yoritomo's nationwide domination through the annexation of Mutsu and Dewa Province by the Kamakura shogunate. It was the last battle of the period of civil war known as the Jishō-Juei War that began in 1180, and its end marked the establishment of the first military government, the Kamakura shogunate.