The 1554 siege of Matsuo was one of many sieges undertaken by the daimyo

Daimyo

is a generic term referring to the powerful territorial lords in pre-modern Japan who ruled most of the country from their vast, hereditary land holdings...

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...

 in his campaign to conquer Japan's Shinano province

Shinano Province

or is an old province of Japan that is now present day Nagano Prefecture.Shinano bordered on Echigo, Etchū, Hida, Kai, Kōzuke, Mikawa, Mino, Musashi, Suruga, and Tōtōmi Provinces...

. This took place during Japan's Sengoku period

Sengoku period

The or Warring States period in Japanese history was a time of social upheaval, political intrigue, and nearly constant military conflict that lasted roughly from the middle of the 15th century to the beginning of the 17th century. The name "Sengoku" was adopted by Japanese historians in reference...

, in which feudal lords (daimyo) vied for control of fiefdoms across the country.

Matsuo castle, in the Ina valley, was controlled by Ogasawara Nobusada; after defeating him, Shingen went on to seize nearby Yoshioka castle as well.