Siege of Koriyama

• Date: 1540
• Location: Aki Province
• Siege

Amako Haruhisa (20,000+) vs. Mori Motonari (8,000)

Amako Haruhisa, who had been steadily advancing the power of the Amako (reaching as far west as Harima in 1538) invaded the Mori lands of Aki Province and forced Motonari to retreat within the walls of Koriyama. Haruhisa, who was determined to eliminate the Mori (a long-time thorn in the Amako's side) once and for all, burned Yoshida (Koriyama’s town) but was unable to dislodge Motonari from Koriyama itself nor entice him to come out. For his part, Motonari contented himself with making small night-time raids on the Amako's supply trains as Haruhisa settled in for a siege. A relief army under Sue Harukata was sent by the Ouchi and forced Haruhisa to retreat with some loss when the latter was attacked by both Harukata and Motonari. This victory, and the death of the former Amako Daimyo Tsunehisa the following year, would encourage the Mori and Ouchi to invade the Amako's Izumo Province in 1542. That campaign, however, was destined to end with Haruhisa raising a victory cry (see First Gassan-Toda).