|Alternate Name||Uchigoya-jo, Yokoo-jo|
|Admin's Rating||★ ☆ ☆ ☆ ☆|
|Historical Site||Local Historic Site|
|Location||Ueda, Nagano Pref.|
|Access||Ueda Sta. (Shinano Railway, Nagano Bullet train), 25 minute bus to Yukimuranosato bus stop (Sugadaira bus from #3 bus stop at Ueda Sta), 10 min walk|
|Visited||March 31, 2016|
|Visitor Info.||mountain trails open any time | Time Required: 30 mins|
|Notes||The site is not well signposted and it took some effort to find where the castle begins and ends. Basically from the Kuromon Gate, the ridge extending to the right (east) was the castle. You can make out some baileys that created the castle. If I were to go again, I would start from here and try to find the trail to Nagao Castle which should be around Shinkoji Temple and take it to Nagao Castle and down to Obiki Castle on the other side. There are many Sanada related castles nearby. It would take several days to see them all.|
The early history of Okkoshi Castle is unclear. The local lord of the Yokoo clan, a vassal of the Murakami, had a home behind this castle. The castle is very small, just occupying one small hilltop ridge that extends between two rivers. It is high enough to provide a good view of the surrounding plains and easily defensible sitting between the two rivers. Though small, it seems like an ideal location for a satellite castle. Nearby, a short walk west, is Obiki Castle, a significantly larger castle, and at the top of the mountain just North of Okkoshi and Obiki Castles is Nagao Castle. This area was an important defense on the roads leading to Ueda and Matsushiro. It would make sense that these three castles all worked together as the main defense for this side of the plain and for watching over these roads. There are also trails from Obiki Castle and the temple behind Okkoshi Castle (Shinkoji) that lead to Nagao Castle.
Yokoo Nobumitsu died at the Battle of Uedahara (1548), despite it being a great victory for the Murakami. His son was too young to become the new lord so the lands went to the Sanada. It is likely the Sanada manned it as one of the fortifications in their rich network around this plain. Even though each castle is not necessarily large nor strong the advanced network of castles around this area creates a formidable defense. The temple (Shinkoji) behind the castle was erected by Sanada Masayuki to his brother who perished at the Battle of Nagashino.