Kagekado Kato, Yoritomo Minamotono's vassal, was appointed Iwamura castle's ruler and to begin construction of it. There are different stories about the construction year, but the dates have been narrowed down to 1185-1195 (the 1st year of Bunji to the 6th year of Kenkyu era). Kagekado's descendants named themselves the Tohyama clan, and after that, occupied eastern Mino until the end of Muromachi/the Sengoku period.
(Mino Province／Gifu Prefecture)
During the age of Kagetou Tohyama, he married Otsuyanokata, Nobunaga Oda's aunt, and adopted Nobunaga's son as his own, becoming Nobunaga's subordinate. In the 3rd year of Genki era (1572) Kagetou died, and Otsuyanokata acted as the ruler of the castle as her son Katsunaga was too young. This is the famous tale of the "Female Ruler".
However, the pressure of Shingen Takeda from the Shinano area gradually became too strong, and Otsuyanokata married Nobutomo Akiyama, the commander of the Mino invasion force and a subordinate of Shingen. Nobunaga was furious, storming down the castle in the 3rd year of Tensho era (1575) and executing both Akiyama and Otsuyanokata via cruxification.
After this, Nobunaga's subordinate Hidetaka Kawajiri became the ruler of the castle, and subsequently Ienori Matsudaira (Ogyuu Matsudaira clan). After Takeda was defeated came Shigetoshi (Ranmaru) Mori, after the Incident at Honnoji came Nagayoshi Mori, after the Battle of Komaki-Nagakute came Tadamasa Mori, after which came Naomasa Tamaru, and lastly after the Battle of Sekigahara came Ienori Matsudaira as rulers of the castle.
During the Edo period the castle became the feudal agency of Iwamura Han, the Ogyuu Matsudaira clan became the ruler, after which came the Niwa clan and back to Ogyuu Matsudaira clan until the late Tokugawa Shogunate.
The castle was built in the mountains, and is one of the three greatest mountain castles. However, the feudal clan lord's housing was situated at the foot of the mountain and performed his duties there. Stone walls still remain and the Taiko turret is restored at the site of the feudal lord's housing.
(2008/10/26 、2013/8/11 )