Tobuki Castle


MusashiTobukijou (4).jpg


Tobukijō was a fort built by the Hōjō to guard the mountain ridge path which traversed the area, but there aren’t many details. A proposed date of 1568 is given for the fort’s construction, as the Hōjō were anticipating the invasion of Kantō by Takeda forces at that time. Other sources say that the castle was constructed before that by the Ôishi Clan. The Ôishi served the Yamanōchi-Uesugi Clan (they held the office of Kantō-kanrei) as deputy governors of Musashi Province, but would later surrender to the Hōjō. Some speculate that the castle was abandoned halfway through being constructed because of landslides, but the neighbourhood name of ‘Nekoya’ is retained, which suggests that some kind of fort or at least a fortified residence was consistently maintained here (the castle is also called Nekoyajō). Since another name for the fort is Nijō, implying a secondary or new castle, it may be that a fortified residence was built here earlier in the Muromachi period, and that the Hōjō expanded it by constructing a dejiro (outer castle). The fort likely hosted a beacon tower, functioning as part of the Hōjō’s signal network.

Visit Notes

Tobukijō, ‘Tōkyō’s Most Dangerous Castle’, is a yamajiro (mountaintop castle) fortification ruin in two parts, or one and a half parts. The site straddles the municipal border between Hachiōji and Akiruno municipalities within the Tōkyō Metropolis. The municipal border follows a mountain ridge which is used as a hiking trail. To the south of the ridge there are a series of terraces with earthworks such as terraced baileys and dorui (earthen ramparts), which appear to protect the ridgeline which runs parallel. Beyond the ridge is a long trench and dorui segment, again running parallel. Beyond here is where things get dicey.

I will join the chorus of bloggers proclaiming the dangers of this site, and offer a warning to any explorers who, happily following the pleasant trail along the ridge, think to casually wonder off to explore this site (Yogo, a blogger I follow, says it’s not a castle worth dying for, though I like that because it implies that there might be castles which would be). In the north, a thin slip of a path running from the trail can be found. This goes to the main enclosures of the fort, but there’s not much left as the structure of the fort has been severely eaten into by landslides.

There are two integral baileys, and in between the first and second is evidence of earthworks such as a trench and dorui. It seems that collapses have effaced every single side of the castle, leaving behind a fragile and spindly husk of a yamajiro. Indeed, there’s not much to see considering the risk one takes in walking the very narrow path with sheer drops on each side to reach it!

I braved the path. I didn’t think it was likely that I would lose my footing, but one should be careful. Besides, I don’t even know if the path is still as I found it, as it may have collapsed further, making this site truly inaccessible (the terrain is made up of sheer cliffs in the north); anyone coming to explore this site should do so in the expectation that they may have to turn back. For this reason, Tobukijō has been called Tōkyō’s most dangerous castle ruin.


Castle Profile
English Name Tobuki Castle
Japanese Name 戸吹城
Alternate Names 二城 (Nijō)・根古屋城 (Nekoyajō)
Founder Ôishi Clan; Hōjō Clan
Year Founded 14th century; 1568
Castle Type Mountaintop
Castle Condition Ruins only
Historical Period Pre Edo Period
Artifacts Dorui, Karabori, Horikiri, Kuruwa, &c.
Features trenches
Visitor Information
Access Approach this site from the south. There is a trail running east-west from… Takiyama Castle?
Visitor Information 24/7 free; mountain
Time Required 40 minutes
Location Akiruno, Tokyo
Coordinates 35° 42' 50.44" N, 139° 16' 41.56" E
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Added to Jcastle 2023
Contributor ART
Admin Year Visited Viewer Contributed
Friends of JCastle
Kojō Seisuiki

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