Sarashina Osaka Castle
It is said that Sarashina-Osakajō was originally built by the Kuwahara Clan. The Kuwahara Clan served the Akasawa Clan who were lords of Shiozaki Castle, but eventually their power eclipsed that of their masters and the Kuwahara Clan took control of Shiozaki Castle and moved there. When from the 1550s the Takeda Clan invaded the area they captured Osakajō. Takeda vassal Hoshina Yoshimasa took over Osakajō and guarded the territory from any resurgent attack by the Ogasawara Clan, who were the nominal hereditary rulers of Shinano Province. With the death of Takeda Shingen in 1582 the Uesugi Clan invaded from Echigo and captured Osakajō, which had been under the command of Hoshina Sakon at that time.
I decided to hike from Shiozakishin Castle to Sarashina-Osakajō. This way took me through a flattened area guarded by two boulders. I don't know its purpose. The name on signboards was inconsistent (佳馬平・桂馬平). The trail went to the peak of Osakayama and then descended. It seems like the path from the peak to the castle ruins was abandoned at some point and I lost it. But using my phone as a compass I went toward the castle site. I came across a gigantic staircase carved out of the mountainside. These terraces were quite overgrown, and so hard to photograph, but impressive "in person". A map online I found shows this place as part of the castle's outer defences, but the map I found on-site didn't. I descended here and then had to scramble back up after crossing a stream.
Eventually, after some difficult climbing, the castle ruin came into view. In the shape of the earthworks along the ridge I could see its rear baileys and a large trench. An abrupt "V"-shape in the ridgeline like this was very easy to appreciate from a distance. Beneath here was a small kuruwa which I descended into and then climbed once again from there to reach the castle's rear baileys. They are small enclosures separated by trenches. These trenches are mostly filled up now but can still be made out. Then I came to the large trench mentioned above. It was about 8m deep. Beyond it is the honmaru (main bailey). Beneath the honmaru are a group of minor baileys terracing the mountainside. It is here that the ishigaki (stone-piled ramparts) can be seen in at least six bands, though collapsed and overgrown in many parts. The terracing is made up of about eight tiers, and the lowest tiers are widest. Very small pocket baileys exist below that.
This ruin is overgrown and in places covered in rusted old junk, like old barrels. In the honmaru there is collapsed structure which looks like it has sunk into the earth. There is a concrete pit here. I saw some bear scratches on a nearby tree and wondered if any bear would be unlucky enough to fall in and get trapped. Due to all of the plant growth it was difficult to follow the ishigaki ruins. However, after a vicious climb, finally coming upon the old ruins and finding so much yamajiro-style ishigaki was very exciting, so I mostly enjoyed the adventure. The map in the honmaru of the castle only shows the main area, not showing the neighbouring terraced area I came by or the lower reaches of the castle I exited via.
|English Name||Sarashina Osaka Castle|
|Year Founded||Sengoku Period|
|Castle Condition||Ruins only|
|Historical Period||Pre Edo Period|
|Artifacts||Kuruwa, Koshikuruwa, Ishigaki, Horikiri, Karabori, Dorui|
|Features||trenches, stone walls|
|Access||Inariyama Station on the Shinonoi Line; 50 minute walk to trail head|
|Visitor Information||24/7 free; mountain|
|Time Required||70 minutes|
|Location||Chikuma, Nagano Prefecture|
|Coordinates||36° 32' 10.25" N, 138° 5' 20.00" E|
|Added to Jcastle||2020|
|Admin Year Visited||Viewer Contributed|