The 1572 siege of Iwamura was concurrent with Takeda Shingen

Takeda Shingen

, of Kai Province, was a preeminent daimyo in feudal Japan with exceptional military prestige in the late stage of the Sengoku period.-Name:Shingen was called "Tarō" or "Katsuchiyo" during his childhood...

's push into Tōtōmi Province

Totomi Province

was a province of Japan in the area of Japan that is today western Shizuoka Prefecture. Tōtōmi bordered on Mikawa, Suruga and Shinano Provinces. Its abbreviated form name was .-History:...

 and the famous Battle of Mikatagahara

Battle of Mikatagahara

The ' was one of the most famous battles of Takeda Shingen's campaigns, and one of the best demonstrations of his cavalry-based tactics.-Background:...

. Akiyama Nobutomo

Akiyama Nobutomo

was a samurai during the Age of Warring States in Japan. He was a retainer in the service of the Takeda family who served as one of the Twenty-Four Generals of Takeda Shingen. Nobutomo also served under Shingen's son, Takeda Katsuyori.-Early career:...

, one of Shingen's "Twenty-Four Generals

Twenty-Four Generals of Takeda Shingen

The Twenty-Four Generals were just one of many historically famous groupings of battle commanders from Japan's Sengoku Period. These Twenty-Four were the most trusted commanders of the armies of Takeda Shingen...

," 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 Tōyama's widow, and took it without any bloodshed. The official keeper of the castle, a seven-year old lord called Gobōmaru, was taken to the Takeda home province of Kai

Kai Province

, also known as , is an old province in Japan in the area of Yamanashi Prefecture. It lies in central Honshū, west of Tokyo, in a landlocked mountainous region that includes Mount Fuji along its border with Shizuoka Prefecture....

as a hostage.