Masamune Submits at Odawara and Loses Aizu

Hideyoshi summoned Masamune to the 1590 campaign against the Hōjō at Odawara. Date forces had recently defeated the Ashina and occupied Aizu. Attendance would place that regional expansion under Hideyoshi’s authority, while refusal risked becoming the next target of his armies.

Masamune traveled to the siege and submitted. Around Odawara, armies from several regions enclosed the Hōjō by land and sea, and Hideyoshi built a headquarters at Ishigakiyama. The Hōjō surrendered; Ujimasa and Ujiteru were ordered to die, while Ujinao was exiled to Kōyasan. The operation demonstrated the penalties attached to resisting Hideyoshi’s decisions.

The Date house survived, but Hideyoshi confiscated Aizu and assigned it to Gamō Ujisato. Further settlement in 1591 moved Masamune to Iwadeyama after fighting in the Kasai–Ōsaki area. Submission preserved a ruling house while changing the territory and base from which it governed. Later stories describe a white death robe or attempted family poisoning, but their details remain uncertain.