In the 1591 Kunohe Rebellion, Ishida Mitsunari, together with Asano Nagamasa, was appointed by Toyotomi Hideyoshi as co-commander of the army sent to pacify Ōshū, and besieged Kunohe Castle, held by the rebel Kunohe Masazane, with over 60,000 troops. After about a month of fighting, the castle fell, ending the rebellion and closing the Sengoku era in the Tōhoku region.