Complete Guide to Hojozu Castle (Imizu City) | The History and Remains of a Flatland Castle that Protected the Shogun from the Etchu Provincial Governor
What is Hojozu Castle?
Hojozu Castle was a flatland castle that once existed on the coast of Nakashinminato, Imizu City, Toyama Prefecture. Also known as Hachifuse Castle and Nago Castle, it functioned as the political and military center of Etchu Province for approximately 400 years, from the Kamakura period to the early Edo period.
Currently, the remains are preserved approximately 2 meters underground at the grounds of Imizu Municipal Hojozu Elementary School and cannot be seen from the surface, but they are carefully protected as a designated historical site of Imizu City. It is known as one of the castle ruins of particularly high historical value in Toyama Prefecture.
Basic Information on Hojo-tsu Castle
- Location: Nakashinminato, Imizu City, Toyama Prefecture (formerly Hojo-tsu Lagoon, Nei District, Etchu Province)
- Castle Type: Flatland Castle (Castle on a coastal plain)
- Construction Period: Late Kamakura period (as a provincial governor’s office)
- Main Lords: Nagoshi clan, Momoi clan, Jinbo clan, Maeda clan
- Year of Abandonment: Early Edo period
- Designation: Imizu City Designated Historic Site
- Current Status: Hojo-tsu Elementary School grounds (remains preserved underground)
History of Hojo-tsu Castle | From the Kamakura Period to the Edo Period
Kamakura Period: Establishment of the Etchu Provincial Governor’s Office
The origins of Hojo-tsu Castle date back to the late Kamakura period. The Kamakura Shogunate established the Etchu Provincial Governor’s Office in this area as a base for governing Etchu Province. The Nagoshi clan, a branch of the Hojo family, was appointed as the governor of Etchu Province, and Nagoshi Tokiari established his residence in Hojo-tsu as the governor of Etchu Province.
The reason Hojo-tsu was chosen was its excellent geographical conditions. Hojo-tsu Lagoon was a natural harbor and had flourished since ancient times as a key point for trade on the Sea of Japan. It also offered easy access to the center of Etchu Province by land, making it an ideal location for a political, military, and economic center.
The Genko War and the Fall of Hojo-tsu Castle (1333)
In 1333, with the fall of the Kamakura Shogunate, Hojo-tsu Castle met a dramatic end. As Emperor Go-Daigo’s anti-shogunate movement spread throughout the country, anti-shogunate forces (the Imperial faction) rose up in Etchu Province as well.
Etchu Governor Nagoshi Tokiari holed up in Hojo-tsu Castle, but was surrounded and isolated by the Imperial faction’s forces. Ultimately, Tokiari set fire to the castle and committed suicide along with 79 members of his family and retainers. This tragic fall of the castle is etched in history as one of the events symbolizing the end of the Kamakura Shogunate.
Muromachi Period: Becoming the Residence of the Jinbo Clan
After the turmoil of the Northern and Southern Courts period, Hojo-tsu Castle was rebuilt during the Muromachi period. In 1443, Jinbo Kunimune, the deputy governor of Etchu Province, established a residence in Hojo-tsu, making it the base for the Jinbo clan to govern Imizu and Nei districts.
The Jinbo clan wielded considerable power within Etchu Province and prospered with Hojo-tsu Castle as their base. Especially during the time of Jinbo Nagamasa, Hojo-tsu Castle became more than just a regional base; it held significant importance.
The Meio Coup and the Protection of Ashikaga Yoshiki (1493-1498)
The most noteworthy event in the history of Hojo-tsu Castle is the development following the Meio Coup of 1493.
As a result of the Meio Coup, Ashikaga Yoshiki (later Yoshitane), the 10th Shogun of the Muromachi Shogunate, was deposed and imprisoned by the Kanrei (deputy shogun) Hosokawa Masamoto. However, Yoshiki managed to escape and fled to Hojo-tsu Castle, seeking refuge with Jinbo Nagamasa of Etchu Province.
Jinbo Nagamasa provided Yoshiki with generous protection, and Hojo-tsu Castle became, for a time, the de facto base of a “shogunate government in exile.” For approximately five years, from 1493 to 1498, Ashikaga Yoshiki stayed in Hojo-tsu, and many shogunate officials, servants, and court nobles traveled to Hojo-tsu during this period.
During this period, Hōjōzu transformed from a regional city in Etchū Province into a city of national political importance. The Shogun’s stay brought in Kyoto culture, dramatically improving Hōjōzu’s cultural level.
Sengoku Period: Attack and Fall of Hōjōzu Castle by Nagao Tamekage
In 1520 (Eishō 17), Nagao Tamekage (father of Uesugi Kenshin), a Sengoku daimyo from Echigo Province, invaded Etchū Province and attacked Hōjōzu Castle. The Jinbō clan fiercely resisted, but the castle ultimately fell. This battle significantly weakened the Jinbō clan.
Subsequently, Etchū Province became the stage for fierce struggles between the Uesugi clan, the Ikkō-ikki rebels, and the rising forces of Oda Nobunaga. Hōjōzu Castle was tossed about by the turbulent times, experiencing an unstable period with frequent changes in its lords.
Edo Period: Maeda Clan Rule and Abandonment
In 1585, when Maeda Toshiie acquired Etchu Province by order of Toyotomi Hideyoshi, Hojo-tsu Castle also came under the control of the Maeda family of the Kaga Domain. However, because the Maeda clan prioritized Toyama Castle and Takaoka Castle, the military importance of Hojo-tsu Castle declined.
In the early Edo period, Hojo-tsu Castle was abandoned and its role came to an end. The castle facilities were gradually dismantled, and the town of Hojo-tsu developed into a port town and commercial city.
Structure and Remains of Hojo-tsu Castle
Castle Layout and Structure
Hojo-tsu Castle was a typical flatland castle, built on flat land along the coast. It is believed that its structure combined the convenience of water transport with defensive capabilities, taking advantage of its location facing Hojo-tsu Lagoon.
Based on historical documents and archaeological excavations, the following structure is estimated:
- Honmaru: The residence of the shugo/castle lord in the center
- Moat: A bailey structure divided by multiple moats
- Earthwork: Earthworks for defense
- Gate: Multiple gates (entrances)
As it was a flatland castle, there were no stone walls; the defense system centered on earthworks and moats. It is presumed that a water moat was also constructed, taking advantage of the topography of the Hojozu Lagoon at the time.
Archaeological Excavations and Artifacts
Archaeological excavations conducted during the Heisei era have gradually revealed the true nature of Hojozu Castle.
During an investigation conducted in conjunction with the reconstruction of Imizu Municipal Hojozu Elementary School, it was confirmed that the remains from that time were preserved in good condition approximately 2 meters underground. The main discoveries include:
- Embankment Layer: A large-scale embankment from the construction of the castle.
- Moat Remains: Traces of a moat several meters wide.
- Postholes: Groups of postholes that formed the foundations of buildings.
- Ceramics: Fragments of ceramics from the medieval to early modern periods.
- Roof Tiles: Fragments of roof tiles used in the buildings.
- Wooden Artifacts: Everyday items from that period.
These excavated artifacts are housed and displayed at the Imizu City Shinminato Museum, providing valuable information about the true nature of Hojo-tsu Castle.
Current Preservation Status
The remains of Hojo-tsu Castle are currently preserved buried beneath the grounds of Hojo-tsu Elementary School. After the Heisei-era survey, the remains were protected with an embankment to prevent damage, and the school facilities were rebuilt on top of it.
This preservation method is called “burial preservation,” a technique that protects the ruins while leaving them underground. It is considered an excellent method that allows for future research and development while being compatible with modern land use.
Highlights and Visitor Guide for Hojo-tsu Castle
Information Board at Hojo-tsu Elementary School
The main point of interest when visiting the Hojo-tsu Castle ruins is the information board located north of Hojo-tsu Elementary School. This board provides detailed information about the history and structure of Hojo-tsu Castle, as well as the results of archaeological excavations.
The information board is located near the main gate of the elementary school, and photography is permitted. However, please avoid entering the school grounds without permission and be considerate of class times.
Nearby Historical Attractions
When visiting the Hojo-tsu Castle ruins, we recommend also visiting the nearby historical spots.
Hojo-tsu Hachimangu Shrine
Hojo-tsu Hachimangu Shrine, located within walking distance of Hojo-tsu Castle, has been revered as a center of local faith since ancient times. The Hōjōzu Hachimangu Autumn Grand Festival (Shinminato Hikiyama Festival), held annually on October 1st, boasts a nearly 400-year tradition and is a magnificent festival featuring the largest number of floats (13) in the prefecture.
In 2021, the “Hikiyama and Tsukiyama Procession of the Hōjōzu Hachimangu Festival” was designated a National Important Intangible Folk Cultural Property. The history of Hōjōzu as a prosperous castle town has been passed down to the present day as a festival culture.
Imizu City Shinminato Museum
The Imizu City Shinminato Museum, which exhibits artifacts and related materials from Hōjōzu Castle, is a must-see. Seeing the actual excavated artifacts allows you to more concretely imagine what Hōjōzu Castle looked like at the time.
The museum also provides a comprehensive overview of Hōjōzu’s history, including its prosperity as a medieval port city and the cultural flourishing during the stay of Ashikaga Yoshizumi.
The Townscape of Uchikawa and Hojo-tsu
The area around Hojo-tsu retains the charming atmosphere characteristic of a port town. The area along the Uchikawa River, in particular, retains a strong sense of its fishing village past, attracting many tourists.
From the medieval to the early modern period, when Hojo-tsu Castle flourished, this region prospered as a hub for trade on the Sea of Japan. A stroll through the town, where you can feel the remnants of that era, is a fascinating experience that can be enjoyed in conjunction with a visit to the castle ruins.
Access Information
Public Transportation
- Transfer to the Manyo Line from Ainokaze Toyama Railway “Kosugi Station”
- Get off at Manyo Line “Nakashinminato Station,” approximately 10 minutes on foot
- Or get off at Manyo Line “Shinmachiguchi Station,” approximately 8 minutes on foot
By Car
- Approximately 20 minutes from Hokuriku Expressway “Kosugi IC”
- Approximately 15 minutes from Noetsu Expressway “Takaoka Kita IC”
Parking
- There is no public parking at Hojozu Elementary School
- Please use nearby public parking lots or the parking lot at Hojozu Hachimangu Shrine
- There is a dedicated parking lot at Imizu City Shinminato Museum
Address: 7-5 Nakashinminato, Imizu City, Toyama Prefecture (Hojozu Elementary School)
Notes for Visitors
- Consideration for School Facilities: Hojozu Elementary School is an active educational facility. Please refrain from visiting during class hours, and noise and disruptive behavior are strictly prohibited.
- The remains are underground: The remains cannot be seen from the surface. Visiting will be about imagining the past through the information boards and the surrounding environment.
- Photography: Photography of the information boards and the exterior of the school building is permitted, but please refrain from photographing children.
- Optimal time to visit: Visiting during the annual festival of Hōjōzu Hachimangu Shrine (October 1st) allows for a deeper appreciation of history.
Hōjōzu Castle and the Jinbō Clan | Sengoku History of Etchū
Genealogy and Power of the Jinbō Clan
The Jinbō clan was a powerful samurai family in Etchū Province. Originally, they served as the deputy governor of Etchū, effectively governing on behalf of the governor, the Shiba clan.
The Jinbō clan’s base was Hōjōzu Castle, from which they expanded their power, mainly in Imizu and Nei districts. At their peak, they controlled a wide area within Etchū Province, becoming something close to an independent Sengoku daimyo.
Jinbo Nagamasa and Ashikaga Yoshizumi
Among the Jinbo clan, Jinbo Nagamasa is particularly famous. He became known nationwide for sheltering Ashikaga Yoshizumi, who had fallen from power in the Meio Coup.
There are various theories about Nagamasa’s motives for accepting Yoshizumi, but the following reasons are considered:
- Securing Legitimacy: Strengthening his own political position by sheltering a legitimate shogun
- Connections with Kyoto: Cultural and economic benefits through building connections with shogunate officials
- Superiority in Etchu: Improving his status within Etchu Province, backed by the authority of the shogun
In fact, during Yoshizumi’s stay, many court nobles and shogunate officials gathered in Hojo-tsu, and Kyoto culture flowed in. As a result, Hojo-tsu developed into a cultural city.
The Later History of the Jinbo Clan
Even after the fall of Hojo-tsu Castle to the attack of Nagao Tamekage, the Jinbo clan struggled to maintain their power in Etchu. However, during the Sengoku period, Etchu became a fierce battleground with a complex web of forces including the Uesugi clan, the Ikkō-ikki rebels, and the Oda clan.
Ultimately, the Jinbo clan declined, and their historical role ended during the Tenshō era with the Maeda clan’s rule over Etchu.
The Place Name and Historical Background of Hōjōzu
The unique place name “Hōjōzu” is thought to originate from the Buddhist “Hōjō-e” ceremony. Hōjō-e is a Buddhist ritual in which captured animals are returned to nature, practicing the teaching against killing.
It is presumed that Hōjō-e was frequently performed in the port town of Hōjōzu from ancient times, and that this became the established place name. While the current place name is written as “Hōshōzu-machi,” historically it was pronounced “Hōjōzu.”
In the Middle Ages, Hōjōzu was not merely a port town, but the political, economic, and cultural center of Etchu Province. As a hub for trade along the Sea of Japan, it was a vibrant international city with active exchanges with Kyoto and the Asian continent, where diverse cultures intersected.
Related Castles in Toyama Prefecture
When visiting Hōjōzu Castle, exploring other major castles in Toyama Prefecture will provide a deeper understanding of the Sengoku period history of Etchū Province.
Toyama Castle (Toyama City)
A central castle in Etchū Province, it was renovated by Maeda Toshinaga. Currently, it is maintained as Toyama Castle Ruins Park, with a replica keep.
Takaoka Castle (Takaoka City)
A modern castle built by Maeda Toshinaga, it formed the foundation of Takaoka’s town development. Currently, it is a popular tourist attraction as Takaoka Old Castle Park.
Masuyama Castle (Tonami City)
One of the important strongholds of the Jinbō clan, it boasts excellent remains as a mountain castle. Designated a national historic site, it is an important castle for understanding the relationship between Hōjōzu Castle and the Jinbō clan.
Moriyama Castle (Takaoka City)
This castle served as a base for the Etchu Ikko-ikki rebellion and is a historical site that tells the story of the complex political situation in Etchu during the Sengoku period.
Summary | Historical Value of Hojo-tsu Castle
Hojo-tsu Castle is currently an “invisible castle site” where the remains cannot be seen from the surface, but its historical value is immeasurable.
Beginning as the Etchu provincial governor’s office during the Kamakura period, its unique experience of sheltering the Shogun of the Muromachi Shogunate, and its history as the political center of Etchu throughout the Sengoku period, occupies an important position in Japanese medieval history.
In particular, the fact that Ashikaga Yoshizumi stayed there for five years is highly valued from a historical perspective as a rare example of a regional city temporarily becoming the “political center of Japan.”
When you visit Imizu City, Toyama Prefecture, be sure to visit the Hojo-tsu Castle ruins, read the information boards, and see the excavated artifacts at the Imizu City Shinminato Museum. As you stroll through the streets of Hōjōzu Hachimangu Shrine and Uchikawa, contemplating the ruins lying dormant underground, you can experience the rich history and culture that has continued since the Middle Ages.
The port town atmosphere and festival culture inherited in the modern Shinminato district of Imizu City are a valuable cultural heritage that conveys the memory of the medieval city that flourished around Hōjōzu Castle.
