Kai Asahiyama Castle
It is thought that this mountain was originally the site of a noroshidai (beacon tower) used by the Takeda Clan. In the post-Takeda, post-Oda period when Kai province erupted into rebellion (that is, in summer of 1582; the lords put in charge by Oda Nobunaga either fled or were captured and slaughtered) and warlords streamed in to conquer it along with neighbouring Shinano, Hōjō Ujinao clashed with Tokugawa Ieyasu in this area. Hōjō forces built the Wakimiko Castle complex to the south, and Asahiyamajō was also constructed as a branch fortification by the Hōjō, though it was never completed. The castle would’ve served to protect the area between Wakamikojō on the frontlines, and Saku County in Shinano, from whence the Kantō folk had advanced. However, Tokugawa alligned-forces cut off the Hōjō's supply lines through Saku. Hōjō Ujinao and Tokugawa Ieyasu reached a peace settlement and the Hōjō withdrew.
Asahiyamajō is a mountaintop fort site in the Takane Township of Hokuto Municipality. Ruins of this fort which was never fully completed include dorui (earthen ramparts), kuruwa (baileys), karabori (dry moats), dobashi (earthen bridges), and other earthworks, such as gate ruins and tatebori (climbing moats). The site is interesting and mysterious. It is easy to reach as it is on a walking trail very close to a forestry road, but any map which pinpoints the castle to the main bailey, one of two of the castle’s integral baileys, may lose some people, as the ruins of the castle are most apparent in the second bailey. Also, whilst the walking trail is mostly kept clear, much of the castle site is heavily overgrown with bamboo grass.
The layout of the castle is interesting. The main bailey, which seems not to have been completed, is large and long. A karabori runs around both the main and second bailey, but was not completed in the east. There is a lowered terraced area along much of the east of the main bailey. The northern entrance to the main bailey has some residual earthworks indicating that there was supposed to be a deep trench here with forward parapets to protect a gate. To the south of the main bailey the second bailey expands outward. There is a trench between the first and second bailey and also a stele with the castle’s name on.
The second bailey is made up of a level portion and then a sloped area, now covered in bamboo grass, which was likely never finished but supposed to be a series of stair-like terraces. The ruins are most impressive in and around the second bailey. There are three entry areas and the whole bailey is surrounded by dorui. Beneath the dorui segments are karabori. The dorui continues descending down the slope. There is a gap in the karabori beneath the lowest southern part, so perhaps this part wasn’t dug in time. In the west the trench is present again, though too full of weeds to show well on photographs, and one practically has to feel one’s way through the bamboo grass to discover the lower dobashi. In the west there are two segments of dorui apparent on either side of the karabori. The trench then climbs and eventually becomes a terrace, looping around, of the main bailey, but it seems clear that it was going to become part of a long, ringing karabori.
There’s lots to marvel about at this strange site, a fort incomplete, but one must be prepared to go though a lot of bamboo grass. I thought the number of entrances into the second bailey, an area which was heavily fortified, was excessive. There are two close together. One is in a projecting angled area which functions as a sort of barbican, and so that seems to have been the actual entrance. The other is thought to have been not a gate, but a passageway into the trench accessed from within the bailey. The reason it appears as an entrance now is because the walking trail goes through it!
In the main bailey there were ‘snowbugs’. Yukimushi (woolly apple aphids) are small flies with fluffy white bodies, and their swarming is like falling snow. They tend to stick to one if one goes through a swarm, as when cycling… I’m not a fan.
This is my 1,000th castle profile contribution to jcastle!
|English Name||Kai Asahiyama Castle|
|Castle Condition||Ruins only|
|Historical Period||Pre Edo Period|
|Artifacts||Dorui, Kuruwa, Karabori, &c.|
|Access||Nearest station is Nagasaka Station on the Chūō Main Line|
|Time Required||60 minutes|
|Location||Hokuto, Yamanashi Prefecture|
|Coordinates||35° 51' 9.40" N, 138° 25' 38.06" E|
|Added to Jcastle||2022|
|Admin Year Visited||Viewer Contributed|
|Friends of JCastle|
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