Historic Ruins

A group of Ainu earthwork fortifications on the Nemuro Peninsula, used for spiritual ceremonies and defense. Among the best-preserved Ainu chashi in Hokkaido.

A medieval fortified settlement near Hakodate built by the Wada clan in the 14th century. One of the Twelve Tachi of Hokkaido, it overlooks Tsugaru Strait.

A 15th-century fortified manor on a coastal bluff in Kaminokuni, once the most powerful stronghold in Hokkaido. Excavations have revealed extensive daily life artifacts of the era.

A 14th-century castle in Hachinohe built by the Nanbu clan in 1334. The main enclosure has been reconstructed and the site is now a national historic site and open-air museum.

A late-medieval castle of the Kitabatake clan near Aomori City, destroyed by the Tsugaru clan in 1578. Its well-preserved earthworks are designated a national historic site.

Headquarters of the Nanbu clan in Sannohe, Aomori, built in 1539. The reconstructed main tower offers panoramic views and houses a museum about Nanbu clan history.

A grand castle built by the Nanbu clan in 1597 atop a granite hill at the confluence of the Kitakami and Nakatsu rivers. Its massive stone walls survive intact and the grounds are a famous cherry blossom park.

Stronghold of the Kunohe clan in northern Iwate, site of the 1591 Kunohe Rebellion against Toyotomi Hideyoshi. Its well-preserved earthworks and stone foundations are a national historic site.

An 8th-century government fortress established in 724 AD as the administrative center for the northeastern frontier. The stone monuments recording its history are among Japan's three great stone inscriptions.

Built by Date Masamune, the legendary 'One-Eyed Dragon', in 1601 on a commanding hill above Sendai. Also known as Aoba Castle, its stone walls and a famous equestrian statue of Date Masamune remain.

Hilltop castle in Osaki, Miyagi, where the young Date Masamune made his base before moving to Sendai. A reconstructed turret and the beautiful stone walls tell the story of the one-eyed warlord's rise.

A dramatic hilltop mountain castle on the Sea of Japan coast in Akita, built by the Ando clan in the 16th century. One of the largest earthwork castles in the Tohoku region, with breathtaking coastal views.

Birthplace of the legendary warlord Uesugi Kenshin and longtime castle of the Uesugi clan in Yonezawa. The ruins sit within a park containing the Uesugi Shrine, dedicated to the Uesugi daimyo.

A hilltop castle founded in 1414, famous for the tragedy of the Nihonmatsu Young Brigade (少年隊) who fought and died here during the 1868 Boshin War. Its stone walls and gates are remarkably well-preserved.

A large mountain castle built by Ashina Moriuji in 1561 overlooking Aizuwakamatsu. Its vast earthworks spread across three ridges, and it served as a refuge castle for the Ashina clan.

A hillside castle near Miharu, famous for the spectacular Miharu Takizakura waterfall cherry tree nearby. The castle was the base of the Tanakura clan and later the Akita clan of the Miharu domain.

Seat of the Mito Tokugawa domain, one of the three main Tokugawa branch families. The castle occupied a narrow ridge between two rivers. A large three-story gate (Ninomaru Otemon) has been reconstructed.

One of the few natural rock castles in Japan, Kasama Castle in Ibaraki used the rocky crags of Mt. Sashiro as its foundation. It served as the stronghold of the Kasama clan for generations.

Known as 'Kamejo' (Turtle Castle) for its island-like appearance surrounded by moats in Lake Kasumigaura. An original turret and gateway remain, making it one of Ibaraki's few remaining castle structures.

The ancestral residence of the Ashikaga clan, founders of the Muromachi shogunate, in Ashikaga City. The site is now occupied by Banna-ji Temple, which retains the original moat and earthwork layout.

A mountain castle dating to the 10th century and stronghold of the Sano clan for over 250 years. Its well-preserved stone walls and multi-layered enclosures spread across a forested ridge above Tochigi plains.

A mountain castle built on steep cliffs near Nasukarasuyama in Tochigi. Nicknamed 'the castle of the crags,' its naturally fortified position and stone walls have been designated a national historic site.

A large earthwork castle in Takasaki, Gunma, built in 1512 and fought over by the Takeda, Uesugi, and Hojo clans. Its massive earthworks and tiered enclosures are among the best-preserved in the Kanto region.

A mountain castle in Ota, Gunma, featuring the earliest stone walls in eastern Japan. Built in 1469 by the Iwamatsuda clan, its sophisticated water management system and stone paving are remarkably modern.

A strategically vital castle on a plateau at the confluence of three rivers in northern Gunma. Once held by Sanada Masayuki, it was dismantled by Tokugawa order but its earthworks and gardens survive.

A dramatic mountain castle clinging to the 803m peak of Mt. Iwabitsuki in Higashiagatsuma. The vertiginous rocky terrain was described as impregnable and was one of the Sanada clan's three key strongholds.

A small but strategically crucial castle on a ridge spur in Minakami, Gunma. Sanada Masayuki built it to counter the Hojo expansion, and the seizure of this castle triggered the Korean Invasions (Odawara Campaign).

Built in 1476 by Nagao Kageharu on a peninsula formed by the Arakawa River, this was the strategic hub of the Hojo clan's northern territories. The earthworks and stone walls are designated a national historic site.

A medieval earthwork fortress in Ranzan, Saitama, believed to be the residence of Hatakeyama Shigeyasu. Its well-preserved moats and earthworks are part of the Musashi Matsuyama Castle historic site.

A compact but intricately designed hill castle in Ranzan, Saitama, considered a masterpiece of Sengoku-era earthwork engineering. Its complex arrangement of enclosures, moats, and ridges is studied by castle scholars worldwide.

Built by Ota Dokan in 1457 and later expanded into the largest castle complex in the world by Tokugawa Ieyasu. The inner palace is now the Imperial Palace; the massive stone walls, moats, and gates remain as Japan's premier historic site.

A large mountain castle built by Hojo Ujiteru on Mt. Shinpuku in 1571. In 1590 it fell to Toyotomi forces in a single day; the stone-paved pathways and bridges have been partially restored in dense forest.

A large hilltop castle in Hachioji built by the Oishi clan in 1521, later used by Hojo Ujiyasu. Its extensive earthworks in the forested Tama Hills are considered one of the finest examples of Sengoku-period castle engineering.

Built by Toyotomi Hideyoshi in just 80 days in 1590 to besiege Odawara Castle. When its forest cover was suddenly felled to reveal the completed stone walls, the demoralized Hojo clan surrendered. A remarkable feat of psychological warfare.

The primary residence of the Takeda clan in Kofu, Yamanashi. Now occupied by Takeda Shrine, the outer moat and earthworks of this fortified manor remain and are a national historic site.

Built by Toyotomi Hideyoshi's retainer in 1583 using sophisticated stone masonry on a central hill in Kofu. Partially reconstructed turrets and the beautiful layered stone walls stand in the heart of the city.

A hilltop castle hastily built by Takeda Katsuyori in 1582 as a last refuge from Oda Nobunaga's invasion. Katsuyori burned it himself after just three months; the earthworks on this scenic bluff in Nirasaki are exceptionally well-preserved.

A unique '穴城' (sunken castle) built lower than the surrounding town on the slopes of Mt. Asama. Founded in the 16th century, its layered stone walls and original gates (Important Cultural Properties) are set within Natsume Soseki's beloved Kaikoen Park.

Mountain headquarters of the legendary warlord Uesugi Kenshin, the 'Dragon of Echigo.' Spread across the ridges of Mt. Kasugayama, this vast castle complex was virtually impregnable and symbolizes Kenshin's military dominance.

A mountain castle in Joetsu, Niigata, where Uesugi Kagekatsu defeated his rival Uesugi Kagetora after Kenshin's death in 1578. The castle burned in the siege and evidence of the destruction is still visible in excavations.

A mountain castle in Tonami, Toyama, that was one of the three great castles of Etchu Province. Its multi-ridge fortifications overlook the Tonami Plain and are now a designated national historic site covered in forest.

A dramatic mountain castle on three ridges above Nanao Bay, built by the Hatakeyama clan in Noto. Uesugi Kenshin besieged it for over a year before finally taking it. The stone walls along the forested trails are among Hokuriku's finest.

The remarkably preserved ruins of the Asakura clan's castle town, buried and forgotten for 400 years until excavations began in 1967. Street layouts, garden stones, and artifacts recreate daily life in a 15th-century castle town. A national special historic site.

At 717 meters elevation, Iwamura is the highest castle in Japan. Founded in 1221 and later controlled by a female lord (女城主おつやの方), its six-tiered stone walls clinging to the mountain ridge are among the most spectacular castle remains in Japan.

A mountain castle built atop enormous granite boulders in Nakatsugawa, Gifu. The ruins feature stone walls seamlessly integrated with the natural rock formations, and on foggy mornings the site creates an ethereal 'castle in the sky' effect.

Built atop a hill overlooking Takayama's old town by Kanamori Nagachika in 1588, Takayama Castle was demolished by Tokugawa order in 1695. The stone walls and earthworks in the forested Shiroyama Park are designated historic sites.

A Hojo clan mountain pass castle on the Tokai Road in Mishima, Shizuoka. Famous for the distinctive rectangular earthwork barriers (障子堀) unique to Hojo construction. Fell to Toyotomi forces in just half a day in 1590.

A castle in Numazu considered the founding stronghold of the Hojo clan's rise to power. Ise Shinkuro (later Hojo Soun) based himself here from 1487 to launch his conquest of the Kanto region. The massive earthworks are a national historic site.

The castle at the center of the famous 1575 Battle of Nagashino, where Oda Nobunaga's arquebusiers devastated the Takeda cavalry. The earthworks at the confluence of two rivers in Shinshiro, Aichi, are a national historic site.

Oda Nobunaga's first castle built on a strategic hill in Komaki, Aichi, in 1563. Later the site of the Battle of Komaki and Nagakute between Toyotomi Hideyoshi and Tokugawa Ieyasu. Excavations have revealed elaborate stone-paved pathways.

Built in 1588 by Gamo Ujisato in Matsusaka, Mie, the former castle town famous for Matsusaka beef. Only the stone walls remain, but they are considered some of the most beautiful in Japan, especially when cherry blossoms bloom within the ruins.

The castle of the Fujido clan and later Todo Takatora in Tsu, the prefectural capital of Mie. Todo Takatora was a master castle builder who contributed to Osaka Castle and others. His statue stands beside the rebuilt turret in the city-center ruins.

The revolutionary first true 'castle' in Japan, built by Oda Nobunaga in 1576 on a hill over Lake Biwa. Its seven-story tower was unprecedented in scale and opulence. Destroyed in 1582 after Nobunaga's assassination, the foundation stones and stone-paved paths remain.

The vast hilltop headquarters of the Rokkaku clan in Higashiomi, Shiga. One of the largest mountain castles in Japan, its multiple enclosures and stone walls spread across Mt. Kinugasa; over 50 warrior clan residences have been identified in excavations.

The former stronghold of Ishida Mitsunari, the villain-hero of the Battle of Sekigahara, on Mt. Sawayama near Hikone. After Sekigahara (1600) the castle was demolished; only earthworks remain on the forested mountain above the Ii Shrine.

A castle in Maizuru, Kyoto, where the elderly Hosokawa Fujitaka (Yusai) famously held off 15,000 Ishida Mitsunari troops with just 500 men during the Battle of Sekigahara (1600). Emperor Go-Yozei intervened to save the castle and its keeper of classical poetry.

A mountain castle on Mt. Kongo where Kusunoki Masashige held off the Kamakura shogunate with a tiny force in 1333. The steep forested trails and earthwork remnants on this sacred mountain recall one of Japan's most celebrated last stands.

Known as 'Japan's Machu Picchu,' Takeda Castle's stone walls dramatically crown a 353m peak above Asago, Hyogo. When morning fog fills the Maruyama River valley, the ruins appear to float above the clouds — one of Japan's most iconic landscapes.

Built by Ogasawara Tadazane in 1619, Akashi Castle in Hyogo features two original corner turrets (National Important Cultural Properties) as the oldest castle structures in the Kinki region. The ruins overlook Akashi Strait and the iconic bridge to Awaji.

The castle of Asano Naganori, whose death by forced seppuku triggered the famous 47 Ronin (Chushingura) revenge story. The restored main gate and tower foundations in Ako, Hyogo, along with nearby Oishi Shrine, are a pilgrimage site for devotees of samurai loyalty.

Built in 1526 atop Mt. Mikuma on Awaji Island, Sumoto Castle commands sweeping views of the Inland Sea. Its beautifully preserved stone walls and the reconstructed keep are complemented by one of Japan's highest stone steps to the castle entrance.

A mountain castle rising 356m above Tanba-Sasayama in the mountains of northern Hyogo. Nicknamed the 'Castle of the Clouds' for its spectacular fog-shrouded appearances, it was the stronghold of the Saito clan and later fought over by Akechi Mitsuhide.

Famous as the site of Oda Nobunaga's 'starvation siege' (干殺し) of 1578–1580, where Hashiba Hideyoshi cut off all supply lines until the castle surrendered after two years. The earthworks on the hill in central Miki City are a national historic site.

A flatland castle in Yamato Koriyama, Nara, built by Toyotomi Hideyoshi's younger brother Hidenaga. Famous for its unusual incorporation of Buddhist statues and carved stones into its walls (逆さ地蔵). The castle town's goldfish breeding tradition survives to this day.

Perched 583 meters atop Mt. Takatori in Nara, this is the highest mountain castle in Japan and one of the most spectacularly located. Its vast stone walls — the best-preserved of any mountain castle — wrap around multiple tiered enclosures in the forest.

A mountain castle on a ridge above the Uda River in Uda, Nara, once held by Oda Nobunaga's third son Nobutaka. The stone walls and earthworks, partially visible from the old Matsuyama streets below, are a designated national historic site.

Built by Asano Nagaakira in 1618 on a rocky bluff above the Kumano River in Shingu, this castle guarded the entrance to the ancient Kumano pilgrimage routes. The unusual black stone walls, made of local volcanic rock, give it a striking appearance.

A flatland castle built on a sea inlet in Tanabe, Wakayama, by Asano Yukinaga in 1606. The restored Kuromonguchi gate and stone walls stand near the port; this was a key castle for the Kishu Tokugawa's southern administration.

Set on a rocky mountain above Tottori City, this castle is infamous as the site of Hashiba Hideyoshi's brutal 'starvation siege' of 1580-81, where the garrison surrendered after eating horses, leather, and grass. The stone walls on the mountain and hill are beautifully preserved.

A multi-tiered castle on a hill overlooking Yonago Bay in western Tottori, built by Nakamura Kazuuji. Four tower bases atop the hill give it a unique silhouette. The stone walls offer views of Mt. Daisen, one of Japan's most beautiful volcanic peaks.

A mountain castle atop a 692m peak in Wakasa, Tottori, with dramatic stone walls tumbling down clifftops. One of the highest stone-walled castles in Japan, it was held by the Yamana clan before being absorbed into Toyotomi territory.

The mountain headquarters of the Amago clan, rulers of eight provinces in western Japan. Set on a 183m peak above the Iinashi River in Yasugi, the stone walls, seven tiers of enclosures, and the story of Yamanakashine's loyalty make this a legendary castle site.

A coastal castle built in 1620 on a hill above Hamada Bay in western Shimane. Its sea-access moat was unique in allowing ships to directly supply the castle; the stone walls are beautifully preserved above the modern city.

Built in 1604 atop a central hill in Tsuyama, Okayama, Tsuyama Castle was the second largest castle in western Japan. Its enormous stone walls — over 77 distinct stone retaining walls — form a spectacular visual display on a hill famous for 1,000 cherry trees.

A mysterious 7th-century Korean-style mountain fortress (朝鮮式山城) in Soja, Okayama, believed to have been built after Japan's defeat at the Battle of Baekgang (663 AD) to defend against Chinese and Korean invasion. The reconstructed West Gate dramatically crowns the ridge.

A flatland castle built on marshy ground in Okayama, famous as the site of Hashiba Hideyoshi's ingenious 1582 water flood siege. Hideyoshi diverted rivers to submerge the castle, and upon learning of Nobunaga's assassination, negotiated a quick surrender.

Headquarters of the Mori clan — one of the most powerful in western Japan — on a 390m mountain in Akitakata, Hiroshima. The vast castle complex had over 270 subsidiary enclosures; the trails through the forest pass stone walls and graves of the Mori lords.

A unique 'floating castle' (浮城) built in 1567 by Kobayakawa Takakage with a harbor moat directly accessible by ship on the Seto Inland Sea. The central turret base (天守台) was incorporated into Mihara Station during the railway era.

A mountain castle on Mt. Shiraga in Fukuyama that served as the Yamana clan's western outpost and later fell to the Mori clan. The stone walls and earthworks offer panoramic views across the Fukuyama plains.

Built by Mori Terumoto after the Battle of Sekigahara on a peninsula surrounded by river and sea in Hagi. The Choshu domain (Hagi) clan who toppled the Tokugawa shogunate in 1868 were raised here; the castle ruins are a UNESCO World Heritage tentative site.

A castle in Shimonoseki (Chofu area) built by the Mori clan's sub-domain, featuring distinctive stone walls rising from the Sea of Kanmon. The site offers views of the narrowest point of the strait to Kyushu, historically crucial for maritime control.

Built by Hachisuka Iemasa in 1586 at the mouth of the Yoshino River, Tokushima Castle's beautiful stone walls rise from the Shinmachi River. The adjacent Tokushima Castle Museum houses feudal-era artifacts, and the park is Tokushima's top cherry blossom spot.

A mountain castle built by the Shoji clan in the 14th century on Mt. Jogaku in Tokushima City. Its stone walls, constructed using unique stacking techniques, are remarkably well-preserved and the site is designated a national historic site.

Known as Tamamo Castle, Takamatsu in Kagawa was a rare sea castle (海城) with ocean water directly filling its moats. Three original turrets (National Important Cultural Properties) survive among the park ruins; the harbor views are spectacular.

A coastal mountain castle in eastern Kagawa built on a peninsula jutting into the Seto Inland Sea. Its stone walls descend to the water's edge, a dramatic example of a sea castle (海城). The surrounding fishing town is one of the best-preserved merchant towns in Shikoku.

A medieval hill castle in Matsuyama that was the seat of the Kono clan, rulers of Iyo Province, for over 200 years. Excavations have revealed samurai residences, household artifacts, and well-preserved earthworks; the site is now within Dogo Park.

Birthplace of Chosokabe Motochika, the 'Last Sengoku Lord' who unified Shikoku, in Nankoku, Kochi. The stone walls and earthworks of this mountain castle survive in good condition, and the adjacent Kochi Prefecture History Museum tells the Chosokabe clan's remarkable story.

Built in 1607 by Kuroda Nagamasa, one of Toyotomi Hideyoshi's key generals. The massive hilltop castle complex in central Fukuoka's Maizuru Park is famous for cherry blossoms. Multiple surviving turrets are Important Cultural Properties; the main tower was demolished in the Meiji era.

A 7th-century Korean-style mountain fortress (朝鮮式山城) on Mt. Shiro in Dazaifu, built by the Yamato government in 665 AD following defeat at Baekgang. Its immense stone and earthwork walls stretch 8km around the mountain, encompassing an area of 55 hectares.

A castle on a low hill overlooking the Chikugo River in Kurume, built by Tanaka Yoshimasa and later held by the Arima clan. The stone walls survive in good condition, and the site's Miimasu Shrine houses a famous collection of feudal-era artifacts.

Built in just five months in 1592 by Toyotomi Hideyoshi as the staging base for his invasions of Korea. Over 130,000 troops assembled here; the castle and its 100+ daimyo residences created Japan's second-largest castle town. The massive stone walls survive in excellent condition.

A 7th-century Korean-style fortress on Tsushima Island built in 667 AD to guard against Tang Chinese and Silla Korean invasion. The sea-facing stone walls dramatically overlook Omura Bay; the castle is accessible only by mountain trail and is one of Japan's most remote historic sites.

The main castle of the So clan who ruled Tsushima and managed Japan's official relations with Korea throughout the Edo period. The stone walls and Yanagidomon gate in Izuhara town are well-preserved, and the nearby Banshoin clan mausoleum is a designated important cultural property.

A castle in Hitoyoshi at the confluence of three rivers, headquarters of the Sagara clan who ruled the domain for 700 years — one of the longest dynastic runs in Japanese history. The remaining stone walls are famous for their 'mushi-kuri' (insect-cage) decorative technique unique to Kyushu.

A flatland castle in Yatsushiro, Kumamoto, built in 1622 on a low mound above the sea by Kato Tadahiro. The moated stone walls and the unusual floating appearance over the rice fields have earned it the nickname 'Floating Castle' (浮城). Only the stone bases remain after Meiji-era demolition.

A castle in Uto, Kumamoto, where Konishi Yukinaga assembled his forces before the 1592 Korean invasions. The stone walls on the hilltop ruins are well-preserved, and Uto Castle was the only Higo province castle allowed to survive the Tokugawa consolidation.

Built on a dramatic plateau of sheer cliffs in Taketa, Oita, Oka Castle inspired composer Taki Rentaro to write 'Kojo no Tsuki' (Moon Over the Ruined Castle), Japan's most beloved song about castle ruins. The vast stone walls wrapping around the clifftops are extraordinarily atmospheric.

A 'sea castle' (海城) built by Otomo Sorin on a peninsula jutting into Usuki Bay in Oita in 1556. Sorin was a Christian daimyo who received the first Portuguese ships here. The stone walls above the harbor and the famous Usuki stone Buddhas (National Treasures) nearby make this a unique historic site.

A hilltop castle built in 1606 by Mori Takamasa in Saiki, Oita. The stone walls dramatically rise from an urban setting; the castle town below retains many historic buildings, and on foggy mornings, the ruins above the clouds create a 'castle in the sky' (天空の城) effect.

A castle built on a rocky hill in Nobeoka, Miyazaki, by Arioka Yukisuke. The unusual stone walls rise directly from the cliff edges; the highest walls (18 meters) are known as 'Chitoseiwa' (千人殺しの石垣) — the walls that could kill a thousand men if they toppled.

A hilltop castle that was the seat of the Shimazu clan's Sadowara branch in Miyazaki. The site includes a reconstructed turret and the Sadowara Historical Folklore Museum; the castle town below preserves several historic samurai residences.

Headquarters of the mighty Shimazu clan, rulers of Satsuma domain and Japan's southernmost major feudal domain. Unusually, this 'castle without a keep' (no tenshu was ever built) relied on the active volcano Sakurajima behind it as natural defense. The reconstructed Goten Museum is Kyushu's finest castle museum.

The best-preserved samurai residential district (fumoto) in Japan, Izumi served as the Shimazu domain's northern military garrison. Over 100 samurai residences with stone walls, hedges, and gates survive; the compact town layout is essentially unchanged from the Edo period.

A mountain castle built by the Sata clan in southern Kagoshima, strategically controlling the southern tip of Kyushu. Its stone walls and earthworks are designated a national historic site; the adjacent Chiran samurai district (武家屋敷) with its Ryukyu-influenced gardens is internationally acclaimed.

Headquarters of the Chiba clan for over 130 years, built in 1469 in Sakura, Chiba. This multi-enclosure hilltop castle was one of the largest in the Kanto region; its earthworks and moat system are designated a national historic site.

A Tokugawa-period hill castle in Sakura, Chiba, built in 1590 and known as the 'castle of the seven mysteries' for its ghost legends. The Samurai District and the National Museum of Japanese History nearby make Sakura one of the richest historic towns in Kanto.

A mountain castle on the slopes above Lake Tsukui in Sagamihara, Kanagawa, built by the Miura clan and later used by the Hojo. Its commanding hilltop position overlooking the modern reservoir creates a dramatic scenic contrast between the ruined stone walls and tranquil water below.

A mountain castle in Hakusan, Ishikawa, built in 1554 as the headquarters of the Ikko-ikki (warrior-monk) resistance against the Oda clan. It was the last Ikko-ikki stronghold to fall in 1581 after a brutal siege; the earthworks on the ridge are a national historic site.

A remote mountain castle built in 1588 by Fujido Takatora in the deep valleys of Kiho, Mie. Constructed to suppress local resistance, its beautifully crafted stone walls on rugged terrain are considered among the finest mountain castle construction in Japan, despite the location's remoteness.

Mountain headquarters of the Azai clan, famous as the castle of Azai Nagamasa and his wife Lady Oichi (Oda Nobunaga's sister). Besieged and destroyed by Nobunaga in 1573, the stone walls and earthworks spread across Mt. Oda in Nagahama, Shiga, are a romantic and tragic historic site.

A hilltop castle and castle town in Toyooka, Hyogo, built by Sengoku Hidehisa in 1604. The picturesque Izushi Castle Town is famous for its Edo-period streetscapes, 35 traditional soba restaurants, and the 5-tiered Inaba Shrine complex. The stone walls crown a wooded hill above the town.

A massive 7th-century earthwork defense wall built in 664 AD across the Chikushi Plain to protect Dazaifu from Tang Chinese and Silla Korean invasion after Japan's defeat at the Battle of Baekgang. The 1.2km-long embankment, up to 13m high with water-filled moats, is the oldest recorded military construction in Japan.

A flatland moat castle in Yanagawa, Fukuoka, once the seat of the Tachibana clan. The city is now more famous for its network of canals, descendants of the castle moat system, where tourists enjoy boat rides through the old merchant quarter. The ruins anchor the city's historic identity.

A castle associated with the Ryuzoji clan in Saga, later absorbed by the Nabeshima domain. The earthworks and stone foundations on the hill in western Saga offer panoramic views of the Ariake Sea, and the site is part of a larger network of Sengoku-era fortifications in the region.

A flatland castle in Fuchu, Hiroshima, that served as a key administrative hub for the Mori clan's vast western domain. Stone walls and earthworks remain in the city center; the site is closely linked to the development of the Fukuyama and Hiroshima castle networks.

A sea-facing castle on a rocky promontory at Yura, Wakayama, built to control the Kii Channel. The stone walls cling to coastal cliffs above Tomogashima Strait, and the strategic position controlling access to Osaka Bay made it a prize fought over by multiple warring clans.

A hilltop castle in Shimanto (formerly Nakamura), Kochi, built by the Ichijo clan who turned this remote valley into a refined 'little Kyoto.' The ruined earthworks and stone walls above the Shimanto River are all that remain of the elegant Ichijo court culture transplanted to deepest Shikoku.

A coastal hill castle in the Sanriku region of Iwate, associated with the Nambu clan's maritime control. The stone walls and earthworks overlooking Miyako Bay are a national historic site that also marks the historical boundary of the Nambu clan's influence in northeastern Japan.

A mountain castle in Kasama, Ibaraki, held by the Kasama clan for generations. Its position on a forested ridge above the ancient castle town features well-preserved stone walls and earthworks. The adjacent Kasama Inari Shrine, Japan's oldest Inari shrine, makes this a doubly historic site.

A hilltop castle in Kakuda, Miyagi, that served as an important stronghold for the Date clan in controlling the southern Mutsu region. The earthworks and moats on the forested hill are well-preserved, and the castle park offers views across the Abukuma highlands.