Yabuhara-toride guarded the important Torii Pass in Kiso. It is thought by some that the fort was originally built by the Kiso Clan to protect against incursions from Kai by the Takeda Clan. In 1549 the Kiso Clan were defeated at Niekawa further north along the valley, but they were able to retreat to Torii Pass where they were reinforced with troops from Fukushimajō, their main base. They then successfully repulsed the enemy at the pass. In 1555 Takeda forces returned. First an advanced party was sent at the end of March, and they reached Yabuhara-toride. But Uesugi Kenshin chose that moment to invade Kawanakajima and so Takeda Shingen called for reinforcements there. That August, however, Takeda forces returned en masse to complete their invasion of Kiso. The Kiso agreed to surrender after clashes. It is also contended that Yabuhara-toride was built by the Takeda-alligned forces under commanders Tada and Kurihara in order to hold ground whilst Takeda Shingen was busy with Uesugi Kenshin at Kawanakajima. During this time of about five months the Kiso tried to (re-)take the fort but failed. Therefore, since Yabuhara-toride was built by at the latest 1555 it played a role in at least one of the Torii Pass battles (of 1549 and 1582), but its existence during the 1549 one is disputed. It is also not known to what extent the fort was utilised during the later battle. In 1555 it appeares that the fort was either built or captured by Takeda forces, playing a signficant role (and perhaps its most significant) in that year too. It should be noted that there is evidence of heavy defences along the ridge toward Yabuhara (and thus toward Kiso territory). It is debated whether these bulwarks were intended to repulse the Kiso Clan by Takeda forces, or whether they were built by the Kiso with a strategic retreat southward in mind. For what little it's worth, after visiting the ruins I'm inclined to believe that the fort was built by Takeda forces in 1555 and then contested by the Kiso; the fort ultimately ended up being used against the Takeda Clan at a critical time...
Kiso Yoshimasa would later rebel against the diminishing Takeda Clan. He was discovered plotting with Oda Nobunaga to overthrow Takeda Katsuyori. In early 1582 Katsuyori dispatched two groups of forces to Kiso ten days apart, but both armies met with defeat at the infamous pass. It was then February and the snow was deep in the valley. Takeda Katsuyori's forces became bogged down in the snow and were routed by the Kiso. These defeats contributed to the fall of Katsuyori to Nobunaga. These famous battles are commemorated throughout the Kiso Valley to this day.
Whilst the Battles of the Torii Pass are famous locally, little information can be found online about Yabuhara-toride. The ruins are divided into four parts which can be accessed from the hiking trail which runs through the Torii Pass on the Yabuhara side of the watershed. These areas consist of three baileys, of which the first is now the site of the Ontake shrine, the second is now Maruyama Park, and the third is the former site of the 'forest weather station'; a final stretch of ruins can be identified along the ridge descending from the third bailey. The trail is actually the old Nakasendō (Main Interior Route) used by countless generations of travellers.
The main bailey complex consists of a central enclosure with terraced sub-baileys bracketing it. To the west the earth rises up into what look like old ramparts in two tiers. The lower sub-bailey has four large pits inside the dorui (earthen ramparts) and I have no idea what to make of this. Normally I'd assume it were the remains of a dug well, but I don't know why there would be four together like this.
The second bailey, 'Maruyama', is just a flat space which serves as a small park. The sides of the slope were made steeper and the portion atop was flattened for use in the fort. Beneath the second bailey where the trail runs there is a right-angled bend with earthen embankments on three sides. This would've made a formidable gate complex for the fort.
The third bailey has a resthouse and the large flattened area which would've constituted the fort's bailey is now labelled on maps of the trail as 'former site of weather station'. According to maps of the fort ruins there should be tatebori (climbing moats) either side of the resthouse which would've formed a narrow chokepoint for entering the bailey; however, these moats must've been filled in because I couldn't see any sign of them. Beneath the third bailey running parallel to the trail is a series of dorui and terraced minor baileys, including a lower part which looked to me like a former gate complex with another angled turn. From here we can see the peak of Tōgeyama, upon which a signal beacon was built by the fort's defenders.
|Pre Edo Period
|Dorui, Kuruwa, Masugata-Koguchi
|Narai Station on the Chūō Line; 10 minute walk to trail head; 25 minute hike to Ontake Shrine. Or, Yabuhara Station on the Chūō Line; 30 minute walk to trail head; 5 minute hike to ruins.
|24/7 free; mountain
|Kiso, Nagano Prefecture
|35° 56' 58.92" N, 137° 47' 34.58" E
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