Onaniwa Tsunamoto

Onaniwa Tsunamoto (1549–1640) was a senior general of the Date Clan who served two generations from Date Terumune, the father of Date Masamune, through Date Masamune himself, and played a crucial role in both political and military affairs of the Date Clan from the Sengoku period into the early Edo period. As his surname suggests—'demon of the garden'—he was feared as a fierce warrior, yet simultaneously demonstrated exceptional diplomatic and administrative acumen.

Tsunamoto earned deep trust from Date Terumune and assumed a central role in the Date Clan's military and administrative affairs. He remained indispensable under Date Masamune's leadership and served as a mediator in negotiations between Masamune and the Toyotomi government during the Ōshū Shikitsuke of 1590 (Toyotomi Hideyoshi's policy for the Tōhoku region). It is said that Tsunamoto's diplomatic acumen saved Masamune during these negotiations and contributed to the Date Clan's survival.

At the Battle of Sekigahara (1600), he sided with the Eastern Army and participated in the conquest of Uesugi territory. In the postwar period, he served as an advisor to Sendai Domain governance and, as Masamune's trusted aide, devoted himself to stabilizing domain administration. Tsunamoto maintained longevity exceeding ninety years—an exceptional lifespan for a Sengoku warrior—and his experience and knowledge contributed significantly to the Date Clan's governance in the early Edo period.

Regarding his connection to blades, Tsunamoto lived within the Date Clan's cultural milieu, which patronized swordsmiths throughout the Tōhoku region, and is believed to have participated in sword authentication and collection. He is said to have been involved in the management of the Date Clan's celebrated meito collection, and his name forms part of the sword culture history of Ōshū.