Siege of Asahiyama Castle
Date: Eighth month of Tenshō 16 (1588)
Location: The Yusa District of Dewa Province
Outcome: The Uesugi forces under Honjō Shigenaga quickly forced surrender by Ikeda Morichika and captured the castle.
The Siege of Asahiyama Castle occurred in Tenshō 16 (1588). In this battle, Honjō Shigenaga led allied forces of the Uesugi and Daihōji-Mutō to lay siege to members of the Mogami army who fled to Asahiyama Castle following their defeat in a field engagement at the Battle of Jūgorigahara on the Shōnai Plain in the Tagawa District of Dewa Province. After their victory at Jūgorigahara in the eighth month of 1588, Shigenaga and Daihōji Yoshikatsu took control of the Shōnai area. In response, retainers of Mogami Yoshiaki including the Shōji siblings and the lord of Asahiyama, Ikeda Sanuki-no-kami Morichika, along with commanders from Yamadate and Sagoshi, raised arms in a plot to attack Kawakita. Shigenaga quickly advanced his forces to Kawakita and attacked the base of the Mogami army at Asahiyama Castle. This led to the surrender of Morichika and capture of Asahiyama.
Shigenaga then chased the remaining forces into Mogami territory, but, exhausted from a series of battles in the Shōnai area, the Uesugi forces were unable to withstand a vigorous counterattack mounted by the Mogami and retreated.