The siege of Iwamura was a military event which occurred in 1572 in Japan, concurrent with

Takeda Shingen , of Kai Province, was a pre-eminent ''daimyō'' in feudal Japan. Known as the "Tiger of Kai", he was one of the most powerful Daimyo, daimyō with exceptional military prestige in the late stage of the Sengoku period. Shingen was a warlord of ...

's push into

Tōtōmi Province was a province of Japan in the area of Japan that is today western Shizuoka Prefecture. Nussbaum, Louis-Frédéric. (2005). "''Tōtōmi''" in . Tōtōmi bordered on Mikawa, Suruga and Shinano Provinces. Its abbreviated form name was . The or ...

and the Battle of Mikatagahara. Akiyama Nobutomo, one of Shingen's " Twenty-Four Generals," set his eye on the great ''yamashiro'' (mountain castle) of Iwamura when Tōyama Kagetō, the commander of the castle's garrison, fell ill and died. Akiyama negotiated the castle's surrender with Lady Otsuya, who was not only Tōyama's widow but the aunt of

Oda Nobunaga was a Japanese '' daimyō'' and one of the leading figures of the Sengoku period. He is regarded as the first "Great Unifier" of Japan. Nobunaga was head of the very powerful Oda clan, and launched a war against other ''daimyō'' to unif ...

. The heir to the castle was a four-year-old boy called Gobōmaru, the fifth son of Oda Nobunaga, who had been given to Tōyama to adopt and raise as his own. Gobomaru was taken to the Takeda home in Kai province as a hostage. In accordance with the surrender treaty, Lady Otsuya married Akiyama. This caused the Takeda-Oda relationship to decline and Nobunaga started a campaign against the Takeda clan.

References

*Turnbull, Stephen (1998). ''The Samurai Sourcebook''. London: Cassell & Co. Iwamura 1572 1572 in Japan Conflicts in 1572 Iwamura 1572 {{Japan-battle-stub