Iwahara Castle (Azumi)
Iwahara Castle was built by the Horigane Clan as a mountaintop redoubt. Their manor house, Horigane Yakata, was located on the plain below. It’s possible that their main quarters were then relocated to the castle’s kyokan, as to be more secure, as the original yakata site was quite distant to the castle. When Takeda Shingen invaded the area the Horigane surrendered and joined him in attacking Hirase Castle to the east of Iwaharajō. They then helped him in his assault on Koiwatake Castle to the north. Takeda rewarded the clan by giving them more lands. Horigane Akimori was killed at the Battle of Kawanakajima.
Iwaharajō is a medieval yamajiro (mountaintop castle) ruin featuring kuruwa (baileys), koshikuruwa (sub-baileys), dorui (earthen ramparts), horikiri (trenches), dobashi (earthen bridges), tatebori (climbing trenches) and other earthworks, as well as some residual stonework. The castle’s profile is fairly narrow, following the ridgeline of the mountain. The shukuruwa (main bailey) is in the centre, and an outer, upper bailey is surrounded by some trenches where the ridgeline forks. The lower bailey spur continues on along a downward sweeping ridge, ending in a straggling bailey with a large boulder. Below here the ridge becomes very narrow and would’ve been easy to defend from the bailey’s ramparts. The castle’s ôte (main entry path) winds up from the mountain foot below, going beneath a long series of terraced mini baileys which form a tertiary spur of the castle layout. The sites most prominent features are its large trenches, and the horikiri to the rear of the shukuruwa is particularly large and deep.
All in all, the castle is a worthwhile yamajiro to visit. At the base of the mountain, where the castle’s kyokan (residential area) may have been, there is also a lot of ishigaki. These stone-piled retaining walls represent the ruins of a temple called Anrakuji. A stone stupa (specifically a hōkyōintō) survives the temple and has been relocated to the village below. The path to the castle goes past the Yamaguchi Shōya Yashiki, the Edo Period residence of the magistrate of Horigane village, and in between two parts of the Aźumino geo-cultural park which feature rural scenes such as terraced fields.
|Azumi Iwahara Castle
|Pre Edo Period
|Kuruwa, Horikiri, Tatebori, Dorui, Koguchi, Kyokan, Dobashi
|trenches, stone walls
|Toyoshina Station on the Oito Line; 12 minute drive or 80 minute walk to trail head.
|24/7; Free; Mountain
|Azumino, Nagano Prefecture
|36° 18' 33.62" N, 137° 49' 51.92" E
|Added to Jcastle
|Admin Year Visited
|Friends of JCastle