Siege of Koriyama (吉田郡山城の戦い Yoshida Kōriyama no tatakai) took place from September, 1540 until January, 1541 in Yoshida, Aki Province, Japan during the Sengoku period. Amago Haruhisa, with 30,000 men, attacked Kōriyama Castle, which belonged to Mōri Motonari and was defended by 8,000 men. When the Ōuchi clan sent an army under the command of Sue Harukata to relieve the siege, the Amako were forced to leave.