Aiba Castle (Gifu Prefecture) Complete Guide: A Thorough Explanation of History, Remains, and Access
Aiba Castle was a medieval flatland castle located in Ono-cho, Ibi-gun, Gifu Prefecture. Built on a plain between the Neo River and the Misui River, it played an important role as a strategic point in Ono-gun, Mino Province. While most of the remains have been lost, the Hachiman Shrine, built on the site of the main keep, still gives a sense of the former castle. This article provides a detailed explanation of Aiba Castle’s history, the changes in its lords, the state of its remains, and access methods.
Basic Information on Aiba Castle
Aiba Castle was a medieval flatland castle located in Ono-gun, Mino Province (present-day Aiba, Ono-cho, Ibi-gun, Gifu Prefecture). The following summarizes the basic information.
Location
Location: Aiba, Ōno-chō, Ibi-gun, Gifu Prefecture (around Hachiman Shrine)
Aiba Castle was built on a plain located between the Neo River and its tributary, the Sansui River. It is near the former Meitetsu Ibi Line Aiba Station, and the current Hachiman Shrine grounds are considered to be the site of the main keep. It is situated slightly higher than the surrounding plain, suggesting that the castle’s layout utilized the natural terrain of the time.
Classification and Structure
Classification: Flatland Castle
Structure: A flatland castle built on a plain, characterized by its location utilizing the Neo River and Sansui River as natural moats. It is thought to have possessed a typical water-based defensive structure for a flatland castle.
Builder
Builder: Aiba Mitsutoshi
According to the *Shinsen Mino-shi* (New Compilation of Mino Province History), Mitsutoshi, son of Toki Mitsuyuki, adopted the Aiba surname and built the castle during the Kenryaku-Kenpo era (circa 1211-1219). The Aiba clan was a branch of the Toki clan, and Aiba Castle was built as part of the Toki clan’s expansion of power in Mino Province.
Year of Construction
Year of Construction: Kenryaku-Kenpo era (circa 1211-1219)
It is believed to have been built in the early Kamakura period and functioned as a base to solidify the Toki clan’s power base in Mino Province.
Castle Tower Structure
Aiba Castle was a medieval flatland castle and did not have a castle tower like those found in early modern castles. It is thought to have had a structure centered around mansions and turrets, characteristic of medieval castles.
Common Names and Alternate Names
While no specific alternative names are known, it’s possible it was called “Aiba Castle” as it was the residence of the Aiba clan.
History of Aiba Castle
Aiba Castle played a significant role in the history of Mino Province for over 300 years, from the Kamakura period to the Sengoku period. Its history is marked by the rise and fall of the Aiba clan and the turbulent battles during the Sengoku period.
Kamakura Period: Construction by the Aiba Clan and the Jokyu War
During the Kenryaku and Kenpo periods (around 1211-1219), Mitsutoshi, son of Toki Mitsuyuki, adopted the Aiba surname and built Aiba Castle. The Toki clan was a powerful samurai family in Mino Province, and the establishment of a castle in this location by the Aiba clan, a branch of the Toki family, demonstrated the expansion of the Toki clan’s power.
However, during the Jōkyū War in 1221, Aiba Mitsutoshi was killed in battle. The Jōkyū War was a conflict in which Emperor Go-Toba attempted to overthrow the Kamakura Shogunate, and many samurai fought on opposing sides. Mitsutoshi’s death was a major blow to the Aiba clan, but the castle continued to be maintained by them.
The Era of Aiba Kuniyori
Aiba Kuniyori, Mitsutoshi’s grandson, became the lord of the castle, and the Aiba clan’s influence was maintained for a certain period. However, detailed records are scarce, and much remains unknown about the Aiba clan’s activities after Kuniyori. It is believed that Aiba Castle was subsequently abandoned.
Tenbun Era: Restoration by Nagaya Kageoki
During the Tenbun era (1532-1555), Nagaya Kageoki, the lord of Tarui Castle, renovated Aiba Castle and moved there as his residence. Nagaya Kageoki was a powerful warlord in Mino Province and served Toki Yorinori.
Toki Yorinori was the head of the Toki clan, the shugo (military governor) of Mino Province, but his conflict with his vassal, Saito Dosan, was deepening. It is believed that Nagaya Kageoki renovated Aiba Castle to strengthen Toki Yorinori’s power base amidst this political tension.
Tenbun 14 (1545): Conquest by Saito Dosan
In Tenbun 14 (1545), Saito Dosan attacked Aiba Castle, and the castle fell. Saito Dosan was a Sengoku period warlord known as the “Viper of Mino,” who seized real power in Mino Province through gekokujo (overthrowing one’s superiors). In the process of expelling Toki Yorinori, whom Nagaya Kageoki served, and gaining control of Mino Province, Aiba Castle also came under Dosan’s control.
After the fall of the castle, the Takatsukasa clan became the lords of Aiba Castle. The Takatsukasa clan was a prestigious noble family, and while there are various theories as to why they became the lords of Aiba Castle, it is believed to have been part of Saito Dosan’s political maneuvering.
1549 (Tenbun 18): Capture and Demolition by Oda Nobuhide
In 1549 (Tenbun 18), Oda Nobuhide (father of Oda Nobunaga) of Owari Province invaded Mino Province and attacked Aiba Castle. While unifying Owari Province, Oda Nobuhide was actively expanding into Mino Province. Aiba Castle fell again to Oda Nobuhide’s attack and was soon abandoned.
Thus, Aiba Castle was attacked twice by two Sengoku warlords, Saito Dosan and Oda Nobuhide, and its role came to an end amidst the turbulent Sengoku period.
Remains and Current State of Aiba Castle
While very few remains of Aiba Castle exist, traces of the former castle can still be seen in the area believed to be the site of the main keep and its surroundings.
Main Keep Site (Hachiman Shrine)
The current grounds of Hachiman Shrine are considered to be the site of Aiba Castle’s main keep. The shrine grounds are slightly higher than the surrounding plains, indicating the former castle’s topography. A marker indicating the Aiba Castle site stands in front of the shrine’s torii gate, and a stone monument stands in front of the main hall.
The shrine itself is still carefully preserved as a center of local faith, and it is a place where one can quietly reflect on history while feeling the atmosphere of the castle ruins.
Pond Believed to be the Moat
To the northeast of Hachiman Shrine is a pond, which is speculated to be the site of the former moat. Artifacts have been unearthed around this pond, providing important evidence supporting the existence of the castle.
Aiba Castle, a flatland castle, is thought to have utilized the natural rivers of the Neo River and Sansui River as outer moats, and further enhanced its defensive capabilities by constructing artificial moats. The pond that remains today is highly likely to be part of these moats.
Excavation of Artifacts
Medieval artifacts have been unearthed near the pond, which is believed to be the remains of a moat. While detailed excavation reports are scarce, fragments of pottery and ceramics have been found, providing clues to the lifestyle of those who lived there during the time the castle was functioning.
Current Landscape
The area around the Aiba Castle ruins is now residential and farmland, and almost all of the castle’s remains have been lost. However, the area centered around the Hachiman Shrine retains place names and street layouts that evoke the former castle town, making it an interesting exploration spot for history enthusiasts.
List of Lords of Aiba Castle
Aiba Castle had multiple lords from the Kamakura period to the Sengoku period. The main lords are listed chronologically below.
Aiba Mitsutoshi
He was the builder of Aiba Castle, constructing it during the Kenryaku-Kenpo era (around 1211-1219). He was the son of Toki Mitsuyuki and the first person to bear the Aiba surname. He died in the Jokyu War (1221).
Aiba Kuniyori
He was the grandson of Aiba Mitsutoshi and succeeded him as lord of the castle. He maintained the power of the Aiba clan, but details of his later life are unknown. It is believed that Aiba Castle was abandoned after Kuniyori.
Nagaya Kageoki
He moved from Tarui Castle during the Tenbun era (1532-1555), renovated Aiba Castle, and made it his residence. The Nagaya clan served under Toki Yorinori, but the castle fell in 1545 during an attack by Saito Dosan. The Nagaya clan was a powerful samurai family in Mino Province, and Nagaya Kageoki played a significant role in the turbulent Sengoku period.
Takatsukasa Clan
After the castle fell to Saito Dosan, the Takatsukasa clan became the castle lords. The Takatsukasa clan was a prestigious noble family, and it’s unclear why they became the lords of Aiba Castle, a samurai castle, but it’s speculated that it was part of Saito Dosan’s political maneuvering. The castle fell in 1549 during an attack by Oda Nobuhide and was subsequently abandoned.
Aiba Castle and Surrounding Castles
Several castles that played a significant role in the history of Mino Province existed around Aiba Castle. Understanding the relationship with these castles clarifies the strategic importance of Aiba Castle.
Karumi Nishi Castle
Located near Aiba Castle, it was also in Ono District, Mino Province. Karumi Nishi Castle was a castle associated with the Toki clan and, along with Aiba Castle, functioned as a regional defense base.
Kitagata Castle
Located in Motosu District, Mino Province (present-day Kitagata Town, Motosu District, Gifu Prefecture), it is known as the residence of the Ando clan. While its direct connection to Aiba Castle is weak, it influenced the power dynamics of the Sengoku period as part of the castle network in Mino Province.
Tarui Castle
This was originally the residence of Nagaya Kageoki. The reason for Nagaya Kageoki’s move to Aiba Castle is unclear, but it may have been a strategic shift in the sphere of influence of Toki Yorinori.
Inabayama Castle (Gifu Castle)
This was the residence of Saito Dosan and a central castle in Mino Province. Aiba Castle was captured by Saito Dosan, as part of his process of bringing the entire Mino Province under his control. Later, Oda Nobunaga captured Inabayama Castle, renamed it Gifu Castle, and used it as a base for his unification of Japan.
How to Access Aiba Castle
This section explains how to access Aiba Castle ruins using both public transport and by car.
Access by Public Transport
Nearest Station: Tarumi Railway Tarumi Line, Morella Gifu Station
Travel Time: Approximately 70 minutes on foot from Morella Gifu Station
The distance from Morella Gifu Station to Aiba Castle ruins (Hachiman Shrine) is approximately 5.5 km, which takes time on foot. Taking a taxi from the station or renting a bicycle is more practical. You can also consider using local buses, but since the number of buses is limited, it is recommended to check the timetable in advance.
The former Meitetsu Ibi Line Aiba Station has been closed and is no longer in use.
Access by Car
Nearest Interchange: Meishin Expressway, Ogaki IC
Travel Time: Approximately 35 minutes from Ogaki IC
From Ogaki IC, take the national highway towards Aiba. For car navigation, enter “Hachiman Shrine (Aiba, Ono-cho, Ibi-gun, Gifu Prefecture)” or “Aiba, Ono-cho, Ibi-gun, Gifu Prefecture.”
Parking Information
You can use the parking lot at the local community center north of Hachiman Shrine (free of charge). However, as it is a local public facility, please use it responsibly and avoid long-term parking.
Estimated Time Required for Visiting Aiba Castle
The average time required to visit the Aiba Castle ruins is approximately 15-20 minutes. This is sufficient if you only want to see the main keep ruins, marker posts, and stone monuments within the Hachiman Shrine grounds, and look around the pond which appears to be the remains of the moat.
However, if you want to fully appreciate the surrounding topography and the atmosphere of the old castle town, or if you want to enjoy taking photos, it’s a good idea to allow 30 minutes to an hour.
Spots around Aiba Castle
Here are some nearby spots you might want to visit when you come to the Aiba Castle ruins.
Morella Gifu
This is a large shopping mall located in Motosu City, Gifu Prefecture. It’s right next to Morella Gifu Station on the Tarumi Railway, and you can enjoy shopping and dining. It’s convenient to stop by before or after visiting the castle ruins.
Neodani Usuzumi Cherry Tree
This ancient cherry tree, over 1500 years old, is located in Neodani, Motosu City, Gifu Prefecture, and is considered one of Japan’s three great cherry trees. It’s about a 40-minute drive from the Aiba Castle ruins, and attracts many tourists in the spring.
Ohno Town Rose Park
This rose park, maintained by Ohno Town, has approximately 2,000 rose bushes planted. The best time to visit is from late May to early June and from mid-October to early November. It’s about a 10-minute drive from the Aiba Castle ruins.
Castles of Ibigawa Town
Ibigawa Town has several medieval castle ruins scattered throughout, making it an interesting area for castle enthusiasts. Visiting them along with Aiba Castle allows you to experience the castle network of western Mino Province.
Points to Note When Visiting Aiba Castle
Please note the following points when visiting the Aiba Castle ruins:
Respect for Private Property
While the grounds of Hachiman Shrine are open to the public, the surrounding area consists of residential and agricultural land. Please be careful not to trespass on private property and be considerate of the lives of local residents during your visit.
Protection of Remains
The remaining remains are valuable cultural assets. Please observe proper etiquette when visiting, such as not touching stone monuments or markers, or disturbing the area around the pond.
Season and Weather
Aiba Castle Ruins are an outdoor facility, and visits may be difficult during rainy weather, extreme heat in summer, or heavy snowfall in winter. We recommend checking the weather before visiting and wearing appropriate clothing and equipment.
Photography
Photography is permitted at Hachiman Shrine and the surrounding area, but please be considerate of the privacy of local residents and avoid including houses or people in your photos.
Historical Significance of Aiba Castle
Aiba Castle is a castle that symbolizes the expansion of the Toki clan’s power in Mino Province and the turbulent Sengoku period. Built during the Kamakura period, it was involved in important events in Japanese history, such as the Jokyu War, Saito Dosan’s rise to power, and Oda Nobuhide’s invasion of Mino.
Although few remains survive, its history is valuable evidence of the changes in the samurai society of Mino Province. In particular, the fact that it was attacked by two Sengoku warlords, Saito Dosan and Oda Nobuhide, indicates Aiba Castle’s strategically important location. Currently, the Aiba Castle ruins are carefully preserved by the local people and serve as a place of worship, housing the Hachiman Shrine. For history enthusiasts and castle fans, it’s a valuable spot where one can quietly reflect on history.
Summary
Aiba Castle was a medieval flatland castle located in Ono-cho, Ibi-gun, Gifu Prefecture, deeply involved in the history of Mino Province from the Kamakura period to the Sengoku period. Built by Aiba Mitsutoshi, it experienced a turbulent history, passing through the Jokyu War, the era of Nagaya Kageoki, and finally being abandoned after being attacked by Saito Dosan and Oda Nobuhide.
Although most of the remains have been lost, traces of the former castle can still be felt, such as the Hachiman Shrine on the site of the main keep and a pond believed to be the remains of the moat. Access is convenient by car, approximately 35 minutes from the Ogaki Interchange, and parking is available.
Visiting the Aiba Castle ruins allows you to experience the medieval history of Mino Province, the rise and fall of the Toki clan, and the history of battles during the Sengoku period. Why not reflect on the historical drama that once unfolded in this tranquil shrine grounds?
References
The following are reference materials useful for studying the history of Aiba Castle:
- *Shinsen Mino-shi*: A local history of Mino Province compiled during the Edo period, containing descriptions of the construction of Aiba Castle and the Aiba clan.
- *Gifu-ken Shi*: A general history of Gifu Prefecture, containing descriptions of castles within the prefecture, including Aiba Castle.
- *Ono-cho Shi*: A town history summarizing the history of Ono Town, which can be expected to contain detailed descriptions of Aiba Castle.
- Various castle research books: Information on Aiba Castle is also included in castle research books published by the Japan Castle Association and local historical research organizations.
By referring to these documents, you can gain a deeper understanding of the history of Aiba Castle.
