Yogaisan Castle




Built in 1520 by Takeda Nobutora. This site served as a regional centre for the Takeda clan and also as a mountain stronghold for Tsutsujigasaki Palace. Yogaisan Castle is a vast mountain castle also protected by Kuma Castle to the south-east. After the demise of the Takeda, the castle briefly came under control of the Tokugawa until it was given over to Kato Mitsuyasu by Toyotomi Hideyoshi. The stone wall remnants you see today are believed to be form this time period. After the Battle of Sekigahara (1600), the Kai Region once again fell under Tokugawa control and the castle was abandoned.

Visit Notes

Most sources tell you to take a bus from the station but there are only a few busses per day and the timings aren't good for hiking the castle. Some also say you can walk from the Tsutsujigasaki Palace but that would be a long uphill walk on paved roads just to get to the Sekisuiji Onsen. I took a taxi (1800 yen) to the onsen from the station. I hiked the castle and walked back to the Tsutsujigasaki Palace and then took the tourist bus from here to Kofu Station and Kofu Castle. This seemed to be a very efficient and effective way of visiting these sites. actually I went down via Kuma Castle from Yogaisan Castle too, but that's a treacherous path I can't recommend for everyone.

It seems there is some confusion how easy it is to climb and how interesting the site it. Personally I thought it was absolutely outstanding. The mountain ridge is bailey after bailey. Each is well defined with nice ruins of gates and entrances and a lot more stonework than you typically find around this area. There are also several trenches you can easily see. From the Sekisuiji Onsen it's a steep but short climb up several switchbacks. It's not a jogging trail but there may be some trail runners who use it. Once you get to the ruins, the rest is easy. A lot of the trees have been thinned out but that also means there are lots of weeds, especially in the summer, so I would recommend visiting in late fall or early spring after the snows melt.

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  • Stonework near the entrance
  • Small bailey overlooking a road
  • Stonework and gate
  • inside the gate
  • Fudo Bailey
  • Stone walls and gate
  • Bailey
  • Entranceway
  • horikiri and stonework
  • Stonework of the horikiri
  • Stonework on the right side
  • Stonework on the right side
  • stonework of the horikiri
  • Bailey entrance
  • Bailey
  • Bailey
  • Stonework and entrance of the Main Bailey
  • Stonework of the entrance
  • Entrance to the Main Bailey
  • Main Bailey
  • Main Bailey entrance
  • Main bailey stone walls
  • Horikiri trench
  • Stonework lined horikiri trench
  • Narrow "earthen bridge"
  • Narrow bailey
  • Bailey Entrance
  • Stonework
  • Stonework
  • Tatebori trenches
  • Map
  • Map

Castle Profile
English Name Yogaisan Castle
Japanese Name 要害山城
Alternate Names Yogaiyama-jo, Yogai-jo, Yogaizan-jo, Sekisuiji-jo, Maruyama-no-shiro
Founder Takeda Nobutora
Year Founded 1520
Castle Type Mountaintop
Castle Condition Ruins only
Designations Next 100 Castles, Top 100 Mountaintop Castles, National Historic Site
Historical Period Pre Edo Period
Features trenches, stone walls
Visitor Information
Access Kofu Sta. (Chou Main line), 20 min bus to Sekisuiji Onsen
Visitor Information Mountain trails, open any time. Start from the Sekisuiji Hot Spring.
Time Required 120-150 mins
Website 4641.html
Location Kofu, Yamanashi Prefecture
Coordinates 35° 42' 11.38" N, 138° 35' 53.77" E
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Added to Jcastle 2012
Contributor Eric
Admin Year Visited 2017
Admin Visits March 18, 2017

(3 votes)
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15 months ago
Score 0++

Yōgaiyamajō, also called Sekisuijō, Yōgaisanjō and Yōgaizanjō, is a yamajiro of epic proportions, containing such features as ishigaki (stone-piled ramparts), primitive masugata koguchi (square formation gate complexes), dorui (earthen ramparts), dobashi (earthen bridges), tatebori (climbing trenches), horikiri (lateral trenches), kuruwa (baileys), and koshikuruwa (sub-baileys). There are at least eight large gate complexes situated one after the other leading up to the shukuruwa (main bailey). Traces of ishigaki can be found throughout the site with large remains to the rear of the shukuruwa where there are also large trench complexes. Notably the rearward climbing moats streak off on each side of the mountain ridge rather than just the north.

Yōgaiyamajō is a highly recommended yamajiro site for Sengoku period mountaintop castle fans. The succession of large and impressive gate remains is really incredible to behold. At the start of the ruin there is an interesting collection of earthworks in the form of a tatebori and dorui which run to the west, in line with the ridge on which the castle was built. The dorui is nobori-dorui, as I’m calling it, or climbing earthen ramparts, and I determined to follow this interesting structure up rather than use the main trail even though the dorui was covered in bamboo. The tatebori continues climbing beyond a sizable bailey. It’s not often we see multiple tatebori segments between intersecting kuruwa like this. This stack is made up of three kuruwa and three tatebori segments. This is all in just the lower area of the castle where the baileys are narrow; further up the baileys become much wider and the ramparts much taller.

Beneath the main portion of the castle to the north side is a multilayered complex of koshikuruwa. This area was very quiet and shaded so that there was still a lot of snow around. The foot prints in the snow were all animal. There is a well here called Suwa Well. Multiple layers of koshikuruwa are all bounded on the eastern front by a very large tatebori which sweeps down the mountainside and looks quite disastrous to fall into.

The shukuruwa one passes through eight gate complexes to reach. The shukuruwa, the centre of the mountain citadel, is surrounded by tall, thick dorui. To the rear is the Ohhorikiri (“Great Trench”), and a large segment of ishigaki can be found here. The ishigaki ensures the drop into the trench is not a pleasant one. There are several smaller baileys thereafter, and one tatebori is of particular note because it is lined on three sides at the top by ishigaki. I clambered on down into this tatebori, taking care not to slip on down and off the mountain, to inspect the ishigaki up close. Again here the ishigaki has retained the uncompromising near-vertical inclines which would’ve made the fortress very lethal in its day.


24 months ago
Score 1++
Epic! Brilliant! Amazing! But probably not for novices. Some knowledge of yamajiro is required to appreciate this wonderful castle ruin. I spent a few hours here.