Nanao Castle Ruins

Nanao Castle Ruins: A Mountain Fortress That Ruled the Noto Peninsula

For roughly 169 years, Nanao Castle commanded the ridgeline above the port town of Nanao on Japan's Noto Peninsula. The Hatakeyama family, military governors of Noto Province, built it and then enlarged it generation after generation until the fortified zone reached about 2.5 kilometers north to south and a kilometer east to west. The whole mountain, known locally as Joyama, became a single defensive complex.

The keep and the residences are long gone. What remains are the carved terraces, the deep cuts dug across the ridge, and the mortarless stone walls of the castle's core. From the main bailey, perched at roughly 300 meters, the view still carries across the rooftops of Nanao, over the bay, and out to Notojima Island. The grounds were designated a National Historic Site in 1934, with an addition to the protected area made in 2011.

The Hatakeyama Century and a One-Year Siege

The Noto branch of the Hatakeyama clan is generally credited with founding the castle in the early fifteenth century, during the Oei or Shocho era. Its first lord, Hatakeyama Mitsunori, chose a spur of the Sekidosan range that divides Noto from Etchu Province. Over the following decades, as conflict spread through the region, later lords kept extending the lines of baileys along the ridges. By the mid-sixteenth century the castle had reached its greatest extent.

At its height the castle was a place of culture as much as defense. A visiting Zen monk from Kyoto's Tofuku-ji temple was so struck by the setting that he likened the castle on its mountaintop to a palace of the heavens, a phrase later preserved in a document describing one of the lords' garden pavilions.

That confidence was tested in 1576, when the warlord Uesugi Kenshin marched into Noto. The defenders held out for about a year. The castle did not fall to a direct assault. Instead, a faction inside the walls argued for surrender while another fought to resist, and the dispute ended with the pro-surrender side opening the gates in 1577. The clan that had wanted to fight on was hunted down in the aftermath, and the Hatakeyama line as rulers of Noto came to an end.

Kenshin did not hold the castle long. After his sudden death the following year, control passed to the forces of Oda Nobunaga, and Maeda Toshiie eventually took the site. By then the age of the mountain fortress was ending. Maeda built a new castle on lower ground closer to the harbor, and Nanao Castle was abandoned around 1589, its long life as the center of Noto over.

Why the Site Is Protected

Nanao Castle is counted among the five great mountain castles of medieval Japan, alongside Odani, Kasugayama, Gassan-Toda, and Kannonji. Because the hilltop was never built over by a later town and escaped destruction in war, the layout of a major sixteenth-century mountain castle survives here with unusual clarity. The 1934 designation recognized exactly that: a rare chance to read the plan of a fortress at the scale its builders intended.

Walking the ridge, the logic of the defenses becomes legible. Flat terraces, each a separate bailey, step down the slopes. The names recorded on the site markers — the main bailey, the second and third baileys, the Yusa residence, the temple quarter — map a working settlement that was also a military machine.

What to Look For on the Mountain

The stone walls below the central baileys are the feature most visitors come for. They are built in the nozura-zumi style, with rough, uncut stones stacked without mortar, and some of the stone is said to have been carried up from the shore at Nanao. The tiered walls rising toward the main bailey are striking in their height, and the stepped path that climbs through them has an almost ceremonial feel.

Look up to the left on the way in from the upper car park and you can see a horikiri, a ditch cut straight through the ridge to sever the main bailey from the neighboring spur. A bridge once spanned the gap, and the defenders could drop it to cut the link in an emergency.

Near the route to the second bailey stands the Kyushaku-ishi, a stone whose name refers to its length of about 2.7 meters. Large stones were symbols of authority, and this one likely marked a gate on the main approach road from the castle town below.

The main bailey itself is a broad open terrace, roughly 50 meters east to west and 40 meters north to south. A small shrine, Joyama Shrine, was placed here in 1942. Lower on the slope, a spring called the Toi-no-mizu has flowed since the days of the Hatakeyama lords and once supplied the garrison; its flow has lessened over the years. In autumn the second bailey is known locally for its colored leaves.

Around the Castle

At the foot of the mountain, the Nanao Castle Historical Museum is the best place to put the ruins in context. It was founded in 1963 by a descendant of the Noto Hatakeyama family and displays excavated finds, including ceramics, alongside weapons and letters in the hand of the castle's lords. A computer-generated reconstruction helps visitors picture the castle as it once stood.

The town of Nanao itself rewards a longer stay. Maeda's replacement castle survives as a park near the harbor, and the hot-spring resort of Wakura Onsen lies a short drive away on the bay. The port has a long reputation for seafood, from winter yellowtail to oysters.

Visitors should be aware that the Noto Peninsula earthquake of January 2024 damaged the castle grounds. The area around the main bailey reopened in December 2024, and the climbing trail was provisionally restored in April 2025. Some sections remained closed as of mid-2025, with short detours in place; the torii of Joyama Shrine was among the structures that collapsed. Restoration work is ongoing, so checking current conditions before a visit is advisable.