The Shinboyamajyo castle was built in the mountain behind Shinbo village, the centre of Miyagawadani valley, and the second biggest castle which Takeda family owned. Especially, there are quite important ruins such as the castle using a foot of the Mountain, Houses and Nekoya.
It is unknown when it was built, but it is certain that Nobukata, the son of Motomitsu Takeda and a brother of Nobutoyo Takeda, who called Miyagawaden owned and he built the Ryusenji in Tenbun 10(1541). He died in Kouji 2(1556) at the age of 36 years old and his son, Hikogoro Nobukata, inherited the castle. It is presumed that the maintenance of the castle had been held during Eiroku era while Nobukata resided.
The main castle was built near the highest mountain ridge (293.6m) and other defending castles were built on the line of mountain ridge. There were also other parts of castle built on branch mountain ridges leading to Otani area and Shinbo area.
These castles had moats, the biggest moat is 13m wide and 10m deep, and other facilities for offence and defence using mountain road. However, there is no record of war left.
Nobukata Takeda fought against Nobunaga Oda as noble lineage of Mr. Seiwa Minamoto's blood, but after Asakura family died out on August Tensho 1(1573), he was sent to Bingo province(eastern part of Hiroshima prefecture) and died in Tensho 13(1585). As the castle lost its owner, it had to also be collapsed.
Explanation 
Shinbo ku
