The fact that the east side of the castle makes use of extensive terracing and the western side uses an array of dropping trench chutes indicates that the castle was gradually developed with each subsequent power that controlled it, and each had its own preferences for the style of defence. The first fort was likely built by the Oh’iwa-Suda Clan, and additions were made by the Uesugi and Takeda forces over time.
The Uesugi Road runs beneath the castle mount to a strategic pass in the mountains. Uesugi Kenshin, as per the name, is said to have used this route to flank Takeda forces, and there is a tradition that Uesugi Kenshin stationed 3,000 knights at the foot of Tsukioijō for use at the Battle of Kawanakajima. The unejōtatebori trench complex at the castle is a feature associated with Uesugi Clan castles, and so it may be that the Uesugi did indeed order the castle renovated. Outside of oral tradition there are no historical records pertaining to this castle so it’s hard to know for sure. The castle was likely captured by Takeda forces in 1557. The ample terracing on the east side of the castle which defends the mountain pass has been interpreted as a feature used at Takeda Clan castles. It would make sense that Takeda Shingen would protect this pass if Uesugi Kenshin or his allies had intended to use it to strike behind enemy lines.
Actually (I may as well bring this up here), there is a strange belief that Takeda Shingen didn’t build castles, preferring to rely on cavalry, because he is supposed to have once said ‘Your people are your castles, your stone walls, your moats; compassion is one’s ally, and enmity one’s enemy (人は城、人は石垣、人は堀、情けは味方、仇は敵なり)’, meaning that people will serve the Takeda gladly due to their compassion. Well, for a start, Takeda Shingen was a brutal conqueror whose troops engaged in many massacres, and, secondly, they had many, many fortifications. Since the Takeda main base was the Tsutsujigasaki Palace, which was a castle really but is sometimes considered below that of a castle (a yakata is usually a fortified manor residence), this idea has proliferated as ignorance of the common people (or, ‘normies’, if you will). Of course the Takeda built and maintained castles – of course! And it looks like they built much of this one too.
I do love a good mountain climb with castle ruins interspersed along the trail, but it sure is tiring. Luckily I was coming downhill to reach Tsukioijō from Amabikijō, and so the hard part was already over (I say even though I had to lower myself gingerly down a series of sheer rocks at one point). I would’ve explored every inch of this interesting site – Tsukioijō – but I had to skip investigating the extensive terracing (though I could see some from above) on the east side of the castle mount because I was quickly running out of time (I had to return the bicycle I had rented to reach the mountain at four (early!)).
Tsukioijō was a beautifully constructed earthworks castle. Features include horikiri (trenches), tatebori (climbing trenches), unejōtatebori (falling trenches in rows), kuruwa (baileys), obikuruwa (ring bailey) and dorui (earthen ramparts), as well as extensive terracing of the many ridges surrounding the main bailey which is at the top of the site. The mountain can be seen from below to have three fronds, and these correspond to the spurs of the fortified space: north spur, west spur, and east spur. The rear of the castle to the south is also worked along the ridge which climbs up to Amabikijō, and is like a raised tail for the castle. The central area of Tsukioijō is bulbous and star-shaped. The central bailey is very well defended with an obi-kuruwa, a huge trench to the rear, terracing to the east, and unejō on the western slope.
|Suda Clan; Uesugi Clan; Takeda Clan
|Pre Edo Period
|Unejōtatebori, Kuruwa, Horikiri, Dorui, &c.
|Nearest station is Suzaka Station on the Nagano Line; recommended to descend from Amabikijō
|24/7 free; mountain
|Takayama, Nagano Prefecture
|36° 39' 18.79" N, 138° 21' 5.08" E
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