All About Ono Castle: A Complete Guide to the History, Highlights, and Access of Ono Castles Scattered Across Japan
There are several castles named “Ono Castle” throughout Japan. Each has its own unique history in a different region, playing a part in regional control and defense during the Sengoku period (Warring States period). This article provides a detailed explanation of Ono Castles scattered throughout various provinces, including Mino, Dewa, Mutsu, Kazusa, Echigo, and Shimotsuke, covering their historical background, castle structure, current status, and visiting guide.
Table of Contents
This article will explain the following topics in detail:
- Overview and Nationwide Distribution of Ono Castle
- Ono Castle in Mino Province (Seki City and Mino City, Gifu Prefecture)
- Ono Castle in Dewa Province (Yuzawa City, Akita Prefecture)
- Ono Castle Group in Mutsu Province
- Ono Castles in Other Regions
- Ono Castle Visitor Guide
- Historical Materials and Research on Ono Castle
Overview of Ono Castle
The name “Ono Castle” exists in various locations throughout Japan, each with its own distinct historical background. The main Ono Castles are listed below.
- Ono Castle, Mino Province (Ono, Seki City, Gifu Prefecture / Higashigahora, Mino City): The residence of the Saito clan, the deputy governor of Mino Province.
- Ono Castle, Dewa Province (Yuzawa City, Akita Prefecture): A mountain castle designated as a historical site by Yuzawa City.
- Ono Castle, Monou District, Mutsu Province: A castle potentially of ancient fortifications.
- Ono Castle, Tamura District, Mutsu Province (Ono Town, Tamura District, Fukushima Prefecture): A medieval mountain castle.
- Ono Castle, Shimotsuke Province (Sano City, Tochigi Prefecture): A branch castle of Karasawayama Castle.
- Ono Castle, Kazusa Province: A castle that existed in Chiba Prefecture.
- Ono Castle, Echigo Province: A castle that existed in Niigata Prefecture.
- Ono Castle, Mino Province (Ogaki City, Gifu Prefecture): The residence of a retainer of Ujiie Bokuzen.
Many of these castles derive their names from the place name “Ono,” and were built in locations reflecting the geographical characteristics and strategic points of each region.
Details of Ono Castle in Mino Province (Seki City/Mino City)
History and Construction Background
Ono Castle in Mino Province is a mountain castle located on the border between Ono in Seki City and Higashigahora in Mino City, Gifu Prefecture. It is also known as Honjoyama Castle and Tochidoyama Castle. It is estimated to have been built around the Daiei era (1521-1528) by the Saito clan, the deputy governor of Mino Province.
The Saito clan was a powerful deputy governor who held real power in Mino Province, and Ono Castle functioned as an important base for strengthening their control over the province. Before the invasion by Oda Nobunaga during the Sengoku period, Mino Province was ruled by Saito Dosan and his family, and Ono Castle is thought to have played a part in their defense network.
Castle Structure and Scale
Ono Castle is a full-fledged mountain castle built on a mountain 423 meters above sea level, on the border between Mino City and Seki City. The scale is as follows:
- East-West Dimensions: Approximately 600 meters
- North-South Dimensions: Approximately 300 meters
- Main Structure: A group of enclosures is spread out from the main enclosure at the mountaintop to the eastern ridge and two ridges extending to the north.
The castle complex has multiple enclosures (kuruwa) arranged around the main enclosure at the mountaintop, exhibiting a typical medieval mountain castle structure utilizing the ridgeline. The layout, which skillfully utilizes the natural terrain, speaks to the high level of castle-building technology of the time.
Current Situation
Currently, the Ono Castle site is a forest, but remains such as enclosures and moats are well-preserved. There are also well-maintained hiking trails, making it a historical site visited by castle enthusiasts and history buffs. However, as it is a full-fledged mountain castle, preparation for hiking is necessary for a visit.
Details of Ono Castle in Mino Province (Ogaki City)
In addition to the Ono Castles in Seki City and Mino City, there was also an Ono Castle in Ogaki City, Gifu Prefecture. This castle is known as the residence of Yokomaku Tatewaki Nobukane, a retainer of Ujiie Hitachi-no-suke Naomoto (Ujiie Bokuzen), the lord of Ogaki Castle.
Historical Background
Ujiie Bokuzen was a samurai of Mino Province during the Sengoku period, serving Saito Dosan and later following Oda Nobunaga. Since his retainer, Yokomaku Nobukane, resided at Ono Castle, it is presumed that this castle served as a subsidiary castle of Ogaki Castle.
Current Situation
Currently, the castle site is within the grounds of Senshoji Temple, and unfortunately, very few castle remains exist. Only a few signs indicating the castle site are located within the temple grounds.
Details of Ono Castle in Dewa Province (Yuzawa City, Akita Prefecture)
History and Overview
Ono Castle in Dewa Province was a mountain castle located in Furudate, Ogachi Izumisawa, Yuzawa City, Akita Prefecture, and is designated as a Yuzawa City Designated Historic Site. This is a strategically important location built near the tip of a hill on the left bank of the Omono River.
Castle Structure
- Location: Hill tip at an elevation of 216 meters, with a relative height difference of 90 meters
- Main Enclosure Size: 40 meters north-south, 100 meters east-west
- Structure: A layout with defensive functions characteristic of a mountain castle
Built in a position overlooking the Omono River, it is thought to have functioned as a base for monitoring river traffic and controlling the region. The 90-meter relative height difference provided sufficient defensive strength to make sieges difficult.
Builder and Historical Role
While historical records are limited regarding the builder and detailed history of Ono Castle in Dewa Province, it is presumed to have been built and maintained by a powerful local clan from the medieval period to the Sengoku period. It was a castle that played a part in the governing system of the southern region of Akita Prefecture.
Current Situation and Highlights
Remains such as baileys and earthworks still exist on the hillside and are protected as cultural properties of Yuzawa City. Visitors can imagine the layout of the castle at the time and enjoy the view of the Omono River basin.
Ono Castle Group in Mutsu Province
Ono Castle, Monou District, Mutsu Province
Ono Castle, believed to have existed in Monou District, Mutsu Province (present-day northern Miyagi Prefecture), is thought to have been an ancient fortified settlement. From the Nara period to the Heian period, the imperial court established many fortified settlements to govern the Tohoku region, and Ono Castle may have been one of them.
Ono Castle, Tamura District, Mutsu Province (Ono Town, Fukushima Prefecture)
Ono Castle, located in Ono Town, Tamura District, Fukushima Prefecture, is known as a medieval mountain castle. A castle site monument and explanatory sign have been erected behind Senkoji Temple, and it is preserved as a local historical heritage site.
Main Features:
- Structure as a medieval mountain castle
- Remains of structures around Senkoji Temple
- An important historical site that tells the story of the region’s history
This castle has been linked to surrounding castles such as Miharu Castle, and it is possible that it played a role in monitoring the transportation route from the Aizu region to the Hamadori area.
Details of Ono Castle in Shimotsuke Province (Sano City, Tochigi Prefecture)
History and Background of Construction
Ono Castle in Shimotsuke Province was a mountain castle located in Sano City, Tochigi Prefecture. It is believed to have been built in the early Tensho era by Ono Hyobu-no-suke Takayoshi, who belonged to the Sano clan, to prepare for attacks from the Ashikaga Nagao clan. This castle played an important role as a branch castle of Karasawayama Castle.
Karasawayama Castle was a strong mountain castle known as the Sano clan’s base, and Ono Castle functioned as a branch castle that played a part in its defense network. It is thought that it was expected to serve as a front-line base amidst the intensifying conflict with the Ashikaga Nagao clan.
Current Situation
Currently, the castle ruins are maintained as “Negoya Forest Park,” and the site of the main keep is now “Yanagiyama Observation Plaza.” Because it’s maintained as a park, it’s an easily accessible historical site, a place enjoyable for families.
From the observation plaza, you can enjoy a panoramic view of Sano city, experiencing the view from the castle as it was in the past.
Other Ono Castles
Ono Castle in Kazusa Province
Regarding Ono Castle, believed to have existed in Chiba Prefecture, detailed historical records are limited, but it is recorded as one of the medieval castles on the Boso Peninsula.
Ono Castle in Echigo Province
Ono Castle, which existed in Niigata Prefecture, is also known as a castle within the sphere of influence of the Uesugi and Nagao clans, but research into its specific location and structure is ongoing.
Onoji Castle (Machida City, Tokyo)
While not strictly “Ono Castle,” Onoji Castle is a related castle. This was a secondary castle built by Oyamada Arishige, the lord of Oyamada Castle, and it is believed that his son, Jiro Shigeyoshi, was in charge of its defense. It is a valuable historical site as a medieval castle remaining within Tokyo.
Ono Castle Visit Guide
Access to Ono Castle, Mino Province (Seki City/Mino City)
Location: Ono, Seki City, Gifu Prefecture / Higashigahora, Mino City
Access:
- By Car: Approximately 15 minutes from the Mino IC on the Tokai-Hokuriku Expressway
- By Public Transportation: Take a taxi from Mino-shi Station on the Nagaragawa Railway
Notes:
- As it is a full-fledged mountain castle, mountain climbing equipment is necessary
- Some parts of the mountain trail are not maintained
- Depending on the season, the undergrowth may be thick
Access to Ono Castle, Dewa Province (Yuzawa City)
Location: Furudate, Ogachi Izumisawa, Yuzawa City, Akita Prefecture
Access:
- By Car: Approximately 20 minutes from the Yuzawa IC on the Yuzawa-Yokote Road
- By Public Transportation: Take a bus or taxi from Yuzawa Station on the JR Ou Main Line
Points of Interest:
- Protected as a Yuzawa City designated historical site
- Magnificent views of the Omono River
- Relatively accessible mountain castle
Access to Ono Castle, Shimotsuke Province (Sano City)
Location: Sano City, Tochigi Prefecture (within Negoya Forest Park)
Access:
- By car: Approximately 15 minutes from the Sano-Tanuma IC on the Kita-Kanto Expressway
- By public transport: Bus from Tanuma Station on the Tobu Sano Line
Facility Information:
- Developed as Negoya Forest Park
- Parking available
- Enjoy the view from the observation plaza
- Easy to visit with family
Access to Ono Castle, Tamura District, Mutsu Province (Fukushima Prefecture)
Location: Ono Town, Tamura District, Fukushima Prefecture (around Senkoji Temple)
Access:
- By car: Approximately 10 minutes from the Ono IC on the Ban-etsu Expressway
- By public transport: Within walking distance from Ono-Shinmachi Station on the JR Ban-etsu East Line
Points of Interest:
- Castle Ruins Monument and Information Board within Senkoji Temple Grounds
- Relatively Easy to Access
- Possible to combine with sightseeing at Miharu Takizakura and other locations
Historical Materials and Research on Ono Castle
Major Historical Materials
Historical materials concerning Ono Castle vary depending on the castle, but the main ones are listed below.
Related to Ono Castle in Mino Province:
- “Mino no Kuni Sho Kyuki” (Records of Various Old Records of Mino Province)
- “Saito Clan Genealogy”
- “Nobunaga Koki” (Chronicle of Lord Nobunaga) (Indirect Description)
Related to Ono Castle in Dewa Province:
- “Akita Prefecture History”
- Local Historical Materials of Yuzawa City
Related to Ono Castle in Mutsu Province:
- “Mutsu Waki” (Records of Ancient Castles and Fortifications)
- Local Historical Materials from Various Regions
Current State of Research
Research on Ono Castle is being conducted by local historians and castle researchers in various regions. In particular, in recent years, the details of the castle structure have been revealed through the creation of layout maps and archaeological excavations.
Main Research Themes:
- Identification of the Castle’s Construction Date
- Genealogy and Changes in Castle Lords
- Relationship with Surrounding Castles
- Role in the Regional Governance System of the Sengoku Period
- Changes in Castle Structure and Technical Characteristics
Historical Significance of Ono Castle
Ono Castles, scattered throughout Japan, have played important roles in their respective regions.
As a Base for Regional Governance
Ono Castles in various locations functioned as bases for the governing systems of shugodai (deputy governors) and powerful local clans. In particular, Ono Castle in Mino Province played a crucial role in maintaining the military and political balance of the region as an important branch castle within the Saito clan’s sphere of influence.
As a Monitoring Base for Transportation Routes
Many Ono Castles were built along rivers and highways, serving to monitor logistics and military movements. The location of Ono Castle in Dewa Province along the Omono River and the arrangement of the Ono Castle group in Mutsu Province clearly demonstrate this function.
Important Resources for Medieval Castle Research
Currently, the Ono Castle complex is a valuable resource for the study of medieval castles. The unique layouts and structures of each castle provide important clues for studying regional differences in castle construction techniques and changes over time.
How to Enjoy Visiting Ono Castle
Observing Castle Remains
When visiting Ono Castle, paying attention to the following remains will allow you to understand the castle’s structure more deeply:
- Kuruwa: A flat, leveled enclosure
- Horikiri: A defensive structure cutting off a ridge
- Dorui: A defensive wall made of piled-up earth
- Koguchi: The entrance to the castle
- Tatebori: A moat dug into a slope
Combining with Nearby Historical Spots
When visiting Ono Castle, combining it with nearby historical spots will allow you to enjoy a more fulfilling historical exploration.
Around Ono Castle in Mino Province:
- Gifu Castle (Inabayama Castle)
- Gujo Hachiman Castle
- Mino Kanayama Castle
Around Ono Castle in Dewa Province:
- Yokote Castle
- Akita Castle Ruins
Around Ono Castle in Shimotsuke Province:
- Karasawayama Castle
- Ashikaga Clan Residence Ruins (Banna-ji Temple)
Around Ono Castle in Mutsu Province:
- Miharu Castle
- Nihonmatsu Castle
- Miharu Takizakura (Takizakura Cherry Tree)
Seasonal Scenery
Ono Castle, a mountain castle, is also attractive for its seasonal natural scenery.
- Spring: A beautiful season with fresh greenery and cherry blossoms. However, early spring, before the undergrowth grows, is the best time to visit.
- Summer: The greenery is dense, and visibility may be obstructed, but you can enjoy a cool walk through the mountain castle.
- Autumn: The autumn foliage is beautiful, making it the best season to visit.
- Winter: The fallen leaves make it easier to observe the ruins, but caution is necessary in snowy areas.
Summary
The Ono Castles scattered throughout Japan are valuable cultural heritage sites, each with its own unique history and characteristics. The historical roles played by each castle are diverse, including the large-scale mountain castle structure of Ono Castle in Mino Province, the location overlooking the Omono River of Ono Castle in Dewa Province, and the role of Ono Castle in Shimotsuke Province as a branch castle of Karasawayama Castle.
Currently, some have been developed into forest parks, while others stand quietly in the mountains. For castle enthusiasts, visiting these Ono Castles offers a valuable opportunity to experience firsthand the changes in regional governance systems and castle construction techniques from the medieval period to the Sengoku period.
When visiting, please prepare according to the location and condition of each castle, and enjoy your historical exploration while prioritizing safety. The group of castles across Japan, all bearing the name Ono Castle, are a prime example of the diversity and richness of Japanese castle history.
As historical research and archaeological excavations progress, it is expected that even more detailed history will be revealed in the future. We encourage you to visit Ono Castle, which tells the story of its region’s history, and experience its charm firsthand.
