CastleMountain castle (yamajiro)Next 100 Fine Castles No. 153
What makes this castle distinctive
The keep stood on posts of different lengths set into holes cut in a giant boulder high above the Kiso River.
Why?
Naegi Castle sits on a rocky peak 432 m high with almost no flat ground. So the keep and other buildings were raised on posts planted in the rock, a method called kakezukuri (built-out construction). The city's Naegi Toyama Historical Museum calls the keep's kakezukuri design unlike anything else. Today an observation deck on a framework of posts stands on the keep site.[1][3][4]
Post holes cut into the boulders and the deck built on a frame of posts; from the deck, the Kiso River, Mt. Ena and the town of Nakatsugawa.
Why it's interesting
The Edo-period keep was a three-tiered building supported by posts set into holes in the rock. The keep site stands about 170 m above the Kiso River, with a 360-degree view; on autumn and winter mornings you may see a sea of clouds.[1][3][4]
Can you see it?
Visible from outsideThe ruins are free and open all year, day and night. Watch for ice in winter.
To the left (north) of the Fubuki-mon gate site, above the third enclosure
What to look at
Tall stone walls stacked on top of and between natural boulders.
Why it's interesting
Oyagura was the castle's largest turret (yagura), said to have risen about 12 m from the foot of its wall. It guarded against attack along the ridge to the north. At Naegi you can see walls built in several different techniques from different periods all in one visit.[5][6][2]
Legend says that when the water supply was cut off, the defenders washed their horses with rice to make it look as if water were plentiful. About 100 similar tales exist across Japan, but Naegi's lacks the usual ending in which the trick is exposed and the castle falls. The museum suggests this is because the Toyama family left the castle on their own when attacked, so it never fell.[7]
Can you see it?
Visible from outsideFreely visible.
At a glance for visitors
Nearest station
from JR Nakatsugawa Station
Climb
Steep climb
Time neededEditors' estimate
About an hour for the ruins; 1.5–2 hours including the museum
Admission
Adults 330 yen; groups of 10+ 270 yen; free for junior high students and younger
Hours
9:30–17:00 (last entry 16:30)
Access
Open to visitors
The ruins are free and generally open all year, all day, though parts may be closed for disasters or repairs. Part of the surrounding walking trail is closed due to rockfall (city notice as of October 2026).
Naegi Castle was built on Shiroyama (Mt. Takamori, 432 m) on the north bank of the Kiso River, which flows east to west through Nakatsugawa. The keep site is about 170 m above the river. The Toyama family is thought to have moved here from Uenaegi, to the north, in 1526, to defend against forces such as the Kiso from Shinano province.[3][8]
02
Historical record
Lost, then retaken before Sekigahara
The eastern Mino region became a battleground first between the Takeda and Oda, then between Toyotomi and Tokugawa forces. In 1583 Toyama Tomotada and his son Tomomasa, attacked by Mori Nagayoshi, left Naegi and joined Tokugawa Ieyasu at Hamamatsu. In 1600, before the Battle of Sekigahara, Tomomasa retook the castle on Ieyasu's orders and returned after 18 years away.[8][3]
03
Historical record
Castle of a tiny domain
Tomomasa became the first lord of the 10,000-koku Naegi domain (han), and 12 generations of the Toyama family ruled until the end of the Edo period. Old castle plans suggest the layout of main, second and third enclosures was complete by the mid-17th century. The museum explains that the keep was deliberately modest so as not to break the shogunate's rules on castles.[3][8][4]
04
Historical record
Torn down in Meiji; one gate survives
The castle buildings were torn down in 1871, and only the stone walls remain. Fubuki-mon, the main gate, was sold at that time to become the gate of a temple in the city. When the temple was rebuilt in 1996, the gate was entrusted to the Naegi Toyama Historical Museum, where it is the only surviving piece of a castle building on view.[3][9][10]
05
Historical record
National Historic Site at 500
In 1981 about 157,000 m² of the castle area was designated a National Historic Site, and in 2017 it was named one of the Zoku Nihon 100 Meijo (the Next 100 Fine Castles of Japan). 2026 marks 500 years since the castle was founded, and the Naegi Toyama Historical Museum is holding an anniversary exhibition.[3][8][11]
The three-tiered keep was built on posts set into the rock (kakezukuri). It was torn down in 1871. A deck on a framework of posts now stands on the site, but it is not a reconstruction of the keep.
The site today
The whole of Shiroyama is a ruin of stone walls with no surviving buildings on site. There is an observation deck on the keep site, and the Naegi Toyama Historical Museum stands at the foot of the hill.
Main buildings
Lost
Keep (tenshu)
Three tiers on posts; torn down in 1871. A deck now stands on the site.[4][3]
Site only
Oyagura (great turret)
Site of the largest turret, with its tall stone walls.[5]
Original, relocated
Fubuki-mon (main gate)
Sold to a temple in 1871; kept and displayed at the Naegi Toyama Historical Museum since 1996.[9][10]
Key facts
Type
Castle
Setting
Mountain castle (yamajiro)built on a mountain; expect a climbEditorial article
Period
Medieval (c.1185–1570s), Early modern (1570s–1871)Editorial article
Keep (tenshu)
Keep lostthe castle had a keep, but it no longer stands (its stone base may remain)Editorial article
Built
1526Japan Castle Foundation
Main lords
Mōri clan, Tōyama clanJapan Castle Foundation
Abandoned
1871Wikipedia (ja)
Remains to see
Stone walls, Moats, Wells, Gates, Baileys / enclosures (kuruwa), Fortified gateways (koguchi), Keep base (tenshudai), Turrets or turret basesEditorial article
Designation
National Historic Site (Naegi Castle ruins) (1981)Editorial article
Selection
Next 100 Fine Castles No. 153Japan Castle Foundation
Visiting
Access
Open to visitors
The ruins are free and generally open all year, all day, though parts may be closed for disasters or repairs. Part of the surrounding walking trail is closed due to rockfall (city notice as of October 2026).
Take the Kitaena Kotsu bus (Tsukechikyo Line) from lane 1 in front of the station, about 12 minutes to the Naegi stop, then walk about 30 minutes. A direct bus from the station to the ruins runs for limited periods in spring and autumn.[1][2]
Checked: 2026-10-03
Hours and admission
Naegi Toyama Historical Museum
Hours
9:30–17:00 (last entry 16:30)
Closed
Mondays (or the next day after a holiday), December 27 – January 5; occasional closures
Admission
Adults 330 yen; groups of 10+ 270 yen; free for junior high students and younger[10][1]
Checked: 2026-10-03
By car / parking
About 10–15 minutes from Nakatsugawa IC on the Chuo Expressway via Shiroyama Bridge; set your navigation to the Naegi Toyama Historical Museum. Car parks A1 and A2 are paid (500 yen for the first hour, 100 yen per 30 minutes after, up to 1,500 yen), with a 200-yen discount if you visit the museum.[1][13][10]
Checked: 2026-10-03
Grounds opening hours
The ruins are generally open all year, all day[1]Checked: 2026-10-03
Time neededEditors' estimate
About an hour for the ruins; 1.5–2 hours including the museum
Steps, slopes and footing
Inside the ruins expect stone paving, uneven paths and steps. It is about 5 minutes from the car park to the Oyagura site and another 5 to the keep deck. There are cliffs and drops, and shaded spots freeze in winter.[1][14]
Wheelchairs and strollers
The ruins keep their natural terrain and are not barrier-free.[1]Checked: 2026-10-03
Toilets and rest
About a 5-minute walk inside the ruins. On museum closing days, its toilets and some free areas are open 9:30–15:30 (not December–February).[1]
English signs / audio guide
Not confirmed
Seasons
Cherry blossoms in early to mid-April and autumn colors in early November. The cherry festival in Naegi Sakura Park in early April includes evening illumination. Early mornings in autumn and winter can bring a sea of clouds.[1]
Photography
Some photography at the museum may require an application; check the museum's guidance.[10]
Works, closures and restrictions
"Naegi Castle 500th Anniversary" exhibition at the museum, July 18 – December 20, 2026. Free admission on October 4 (Naegi Castle Festival) and November 3 (Culture Day).[8]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
Good for anyone who enjoys reading terrain and stone walls even without buildings, and for view seekers. It is a mountain castle, but the walk from the car park to the keep site is short enough for non-hikers.
What makes it interesting
The highlight is how rock and stonework combine. At Oyagura and the keep site, look for walls stacked on and between boulders, and for post holes cut into the rock.
Before you go
There are no buildings on site, and the deck on the keep site is not a reconstruction. Footing is rough and there are drop-offs, so wear good shoes, and beware of ice in winter.
Ways to enjoy it
Look at the scale model in the museum before you climb; it makes it much easier to picture how the buildings perched on the rock. The view of Shiroyama from the bridges over the Kiso River is also striking.
Photos
Visitor reviews
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Open questions
The name "Red Wall Castle" comes from the tradition that its walls were bare red earth rather than white plaster. A dragon legend is told as the reason, but another view is simply that the domain lacked money.
The 1526 founding date is based on the city's estimate that the Toyama family moved here that year.
When the deck on the keep site was built, and whether there is English signage, could not be confirmed.
AlpsdakeCC BY-SA 4.0Wikimedia Commons
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