CastleMountain castle (yamajiro)Japan's 100 Fine Castles No. 32
What makes this castle distinctive
Uesugi Kenshin's castle had no stone walls and no keep: it was carved out of an entire mountain.
Why?
Kasugayama is a mountain castle (yamajiro) that used the whole of Mount Kasuga, about 180 m high, and its grounds span roughly 2 km from east to west and north to south. Leveled baileys (kuruwa), dry moats and earthen ramparts were stacked across the mountain, and at its foot an outer defense line (sogamae) of moats and ramparts ran for about 1.2 km. No buildings survive; the shaped land itself is the castle.[1][9]
The honmaru (main bailey) and the so-called keep platform near the summit, about 30 minutes' walk from Kasugayama Shrine with stops along the way.
What to look at
The Sea of Japan and the town of Naoetsu to the north, the Kubiki Plain spreading east, and the mountains around it.
Why it's interesting
The official description of the national historic site says the summit commands a wide view, enough to keep watch over the castle's satellite forts. Kenshin is thought to have looked out over this same landscape while keeping Echigo Province and its castles in check.[7][10][4]
Can you see it?
Partly visibleReaching the honmaru means a mountain hike. The keep platform cracked in the 2024 Noto Peninsula Earthquake, and some roped-off areas are closed (city notice as of July 2024).
Just below the honmaru and keep platform, on the west side.
What to look at
The round opening of the well and the water inside it.
Why it's interesting
Water is the biggest problem for any mountain castle. The 1935 national historic site description notes that this well does not dry up even in summer, and it still holds water today, despite sitting high on the mountain. It is one reason the castle could withstand a siege.[7][10]
Can you see it?
Visible from outsideFreely visible beside the trail.
03
The outer moat line and the Historic Site Plaza
Where
The eastern foot of the mountain, at the Kasugayama Castle Historic Site Plaza next to the Monogatarikan visitor center.
What to look at
Earthen ramparts, a moat, a road and post-built buildings reconstructed from excavation findings.
Why it's interesting
A key feature of Kasugayama is its sogamae, a line of moats and ramparts about 1.2 km long enclosing the foot of the mountain, where retainers' houses and dry moats spread out. At the plaza you can see that the castle reached all the way down from the summit. The irises in the Kenmotsu Moat are at their best in early May.[1][2][11]
Can you see it?
Visible from outsideThe plaza is open to walk around. The Monogatarikan is closed on Mondays and in winter (December–February).
At a glance for visitors
Nearest station
40 min walk from Kasugayama Station
Climb
Steep climb
Time neededEditors' estimate
About 1.5–2 hours for the hike from Kasugayama Shrine to the honmaru and back (the official model course takes about 1 hour 40 minutes).
Admission
Free
Hours
9:00–16:30
Access
Open to visitors
The castle site (the whole mountain) is free to walk. Part of the keep platform, damaged in the 2024 earthquake, is roped off. Visitors are warned about bears; free bear bells can be borrowed at the Kasugayama Tourist Information Center (April–October) and the Archaeological Center (late March–early December). No fires are allowed on the site. The Japan 100 Castles stamp is at the Monogatarikan (left at the entrance on closing days), or at the Archaeological Center during the winter closure.
Kasugayama Castle was built as a fortress protecting Echigo-Fuchu, the provincial capital around today's Naoetsu. Nobody knows exactly when it was first built, but it appears in a document from 1513, so it was already in use as a mountain castle by then. From the summit, defenders could see across the plain to the sea and to the castle's satellite forts.[1][7]
02
Scholarly interpretation
Expanded by Kenshin, Kagekatsu and the Hori
Kasugayama is famous as the home of Uesugi Kenshin, one of the great warlords of the Sengoku (Warring States) period. But the castle probably reached its full size only in the late 16th century, under Kenshin, his adopted son Kagekatsu, and then the Hori family. It seems to have grown in stages: from a small fort on the summit, south into large flat baileys, then a residential area, and finally the outer moat line at the mountain's foot.[1]
03
Scholarly interpretation
Castle history in one place
The site falls into four groups: the baileys from the honmaru down to Kasugayama Shrine, a flat area spreading south of the honmaru, the residential remains, and the outer moat line at the foot. Joetsu City notes that it is rare for a mountain castle to have all of these joined without a break, making it a valuable place to trace how castle building changed from the medieval to the early modern era.[1]
04
Historical record
Kenshin's death and a war over succession
In March 1578, Kenshin died suddenly as he prepared to march on the Kanto region. He had not formally chosen between his two adopted sons, Kagekatsu and Kagetora, and the war between them (the Otate Rebellion) ended with Kagekatsu as master of Kasugayama. In 1598 Toyotomi Hideyoshi transferred Kagekatsu to Aizu, and the Hori family took over the castle.[17][6]
05
Historical record
From mountain to plain
In 1607 the Hori built Fukushima Castle, the first flatland castle in Echigo, on low ground near the sea and rivers, and moved there. Kasugayama is said to have been abandoned around this time. None of its buildings survive, but its dry moats, earthen ramparts and great well still show the features of a mountain castle.[6][9][12]
06
Historical record
Protecting and presenting the site
In 1935 the main baileys around the honmaru were designated a National Historic Site, and further areas, including outlying forts and part of the outer moat line, were added in 1974, 1980 and 2000. At the foot of the mountain, a plaza recreates ramparts and moats based on excavations. To make the earthworks easier to see, the city is now cutting planted cedars using a photo from about 100 years ago as a guide, and it is surveying the ground with a view to restoring the outer moats and ramparts.[1][7][13][15]
Kasugayama Castle first appears in a surviving document[1]
Uesugi Kenshin dies suddenly; the Otate Rebellion over his succession begins[17][14]
Uesugi Kagekatsu moves to Aizu; the Hori family takes over[6]
The Hori move to newly built Fukushima Castle, and Kasugayama falls out of use[6][12]
Kasugayama Shrine, dedicated to Kenshin, is founded[10]
Designated a National Historic Site (expanded in 1974, 1980 and 2000)[1][7]
Buildings and remains
The keep today
Not yet confirmed
A spot near the summit is called the keep platform, but whether a keep ever stood there is unknown (the Japan Castle Foundation lists only a "traditional keep platform"). The stone walls and keeps drawn on old pictorial maps are thought to be largely imaginary, and no stone walls or roof tiles have reportedly been found in excavations.
The site today
The whole mountain is a National Historic Site, and trails lead past the bailey sites. Kasugayama Shrine and a statue of Kenshin stand partway up, and the Historic Site Plaza, the Monogatarikan visitor center and the Joetsu City Archaeological Center are at the foot.
Main buildings
Modern reconstruction
Bishamon-do hall
The hall where Kenshin is said to have prayed for victory before battle. The current building dates from 1931 (secondary source).[10][12]
Modern reconstruction
Ramparts, moat and post-built buildings at the Historic Site Plaza
Reconstructed from features confirmed by excavation.[2]
Key facts
Type
Castle
Setting
Mountain castle (yamajiro)built on a mountain; expect a climbEditorial article
Period
Medieval (c.1185–1570s)Editorial article
Keep (tenshu)
Not yet confirmedwhether a keep existed is still being checkedEditorial article
Built by
Uesugi Kenshin, Uesugi clan, Nagao TamekageJapan Castle Foundation
Main lords
Uesugi clan, Hori clan, Nagao clanJapan Castle Foundation
National Historic Site (Kasugayama Castle ruins) (1935)Editorial article
Selection
Japan's 100 Fine Castles No. 32Japan Castle Foundation
Visiting
Access
Open to visitors
The castle site (the whole mountain) is free to walk. Part of the keep platform, damaged in the 2024 earthquake, is roped off. Visitors are warned about bears; free bear bells can be borrowed at the Kasugayama Tourist Information Center (April–October) and the Archaeological Center (late March–early December). No fires are allowed on the site. The Japan 100 Castles stamp is at the Monogatarikan (left at the entrance on closing days), or at the Archaeological Center during the winter closure.
Address
Nakayashiki and surrounding area, Joetsu, Niigata 943-0819[9][1]
Checked: 2026-10-03
Nearest stations and how to get there
Kasugayama StationEchigo Tokimeki Railway Myoko Haneuma Line
about 40 min walk · Steep climb
About 40 minutes on foot to Kasugayama Shrine and the Kenshin statue, uphill all the way from the Archaeological Center. By Kubiki Bus, it is 20 minutes on foot from the Nakayashiki stop or 15 minutes from the Maizo Bunkazai Center-mae stop (both to the shrine). From Joetsumyoko Station on the Hokuriku Shinkansen, a taxi to the Archaeological Center takes about 20 minutes.[9][3]
Checked: 2026-10-03
Hours and admission
Kasugayama Castle Monogatarikan (visitor center)
Hours
9:00–16:30
Closed
Mondays (or the next day if Monday is a holiday) and in winter (December 1 to the end of February). Open every day during Golden Week and the summer holidays (July 25–August 31 in 2026).
About 15 minutes from Joetsu IC on the Hokuriku Expressway, or 20 minutes from Joetsu-Takada IC on the Joshin-etsu Expressway. Parking below Kasugayama Shrine (30 spaces, free, buses OK) and at the Ote-michi lot (10 spaces, free).[9]
Checked: 2026-10-03
Grounds opening hours
No set opening hours for the castle site could be confirmedChecked: 2026-10-03
Time neededEditors' estimate
About 1.5–2 hours for the hike from Kasugayama Shrine to the honmaru and back (the official model course takes about 1 hour 40 minutes).
Steps, slopes and footing
From Kasugayama Shrine to the honmaru it is a mountain trail with continuous slopes and steps. The road from the Archaeological Center up to the shrine is also uphill.[9][10]
Wheelchairs and strollers
Not confirmed (the mountain trails are likely unsuitable for wheelchairs)Checked: 2026-10-03
Toilets and rest
There are toilets at the parking lot below Kasugayama Shrine; the city plans to renovate them in fiscal 2026.[14]
English signs / audio guide
The Japan Tourism Agency has produced and published English explanations of Uesugi Kenshin and the castle site, according to the city. How much English signage there is on site is not confirmed.[14]
Seasons
The irises in the Kenmotsu Moat at the Historic Site Plaza peak in early May, and wild cherries bloom on the mountain in spring. Snow falls in winter, and the Monogatarikan closes from December to February.[2][1]
Photography
Not confirmed
Works, closures and restrictions
Part of the keep platform is closed due to damage from the 2024 Noto Peninsula Earthquake. Watch out for bears (free bear bells are available). The city is carrying out work such as cutting cedars around the Senkanmon gate site.[4][5][15]Checked: 2026-10-03
Suggested routes
Kasugayama Castle in depth (official model course) 100 min
Kenshin statue (pick up the "Kasugayama Castle Ruins" leaflet)
Kasugayama Shrine
Senkanmon gate site
Naoe residence site
Bishamon-do hall
Honmaru and keep platform
Great well (Oido)
Uesugi Kagekatsu residence site
Kakizaki residence site
Return to Kasugayama Shrine
The official model course from Joetsu Tourism Navi (excluding the drive from Joetsu IC). The walk back from the Kakizaki residence site to the shrine takes about 50 minutes. The leaflet is in a small hut on the way from the statue to the shrine. Part of the keep platform is closed.
A temple founded in 1497 by Kenshin's grandfather, Nagao Yoshikage. Kenshin is said to have studied here under the monk Tenshitsu Koiku from age 7 to 14.[9]
City museum in Takada Castle Park, covering how power moved between Kasugayama, Fukushima and Takada castles.[16]
Checked: 2026-10-03
Editors' guide
An editorial guide based on sources and confirmed information — not a first-hand visit report.
Who will enjoy it
For fans of Uesugi Kenshin, anyone who wants to see how an earthwork castle was shaped rather than keeps and stone walls, and those who like combining a hike with Sengoku history.
What makes it interesting
Beyond the view from the honmaru and the great well, watch for the steps of the baileys and dry moats along the trail. Residence sites carry the names of figures such as Naoe Kanetsugu, Kagekatsu and Kakizaki Kageie, giving a sense that the whole mountain was like a town.
Before you go
This is a real hike, so wear good shoes and bring water. Bear warnings are posted, so borrowing a bear bell is a good idea. Snow covers the mountain in winter.
Ways to enjoy it
Start at the Archaeological Center (Kenshin Sengoku Picture Scroll Hall) at the foot of the mountain and study its diorama of the whole castle before climbing; it makes it easier to tell where you are. On the way back, stop at the Historic Site Plaza to see the reconstructed ramparts and moat, and you will have experienced both the summit and the base of the castle.
Photos
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Open questions
When and by whom the castle was first built is unclear. One theory is that the Uesugi, governors of Echigo, built it in the 14th century (secondary source).
Whether there was ever a keep is unknown; "keep platform" is a traditional name.
The 1607 abandonment date comes from a secondary source; city materials state that the Hori built Fukushima Castle in 1607.
The stories that Kenshin prayed at Bishamon-do and studied at Rinsen-ji are presented as tradition.
The keep platform restrictions are from a city notice dated July 2024; the current status is unconfirmed. Site hours, accessibility and photo rules could not be confirmed either.
ELKCC BY-SA 3.0Wikimedia Commons
