Complete Guide to Tsubakio Castle (Nara City, Nara Prefecture) | A Thorough Explanation of the History and Highlights of the Three Great Mountain Castles of Yamato
What is Tsubakio Castle?
Tsubakio Castle is a Sengoku period mountain castle located in Shiroyama, Kitatsubakio-cho, Nara City, Nara Prefecture. The castle commonly referred to as Tsubakio Castle is actually “Tsubaoka-jo,” also known as “Tsutsuiyama Castle” and “Shuro Castle.”
As an important strategic point in Yamato Province (present-day Nara Prefecture) during the Sengoku period, it is a historically valuable castle that served as the stage for conflicts between the Tsutsui and Matsunaga clans. Currently, it is counted as one of the “Three Great Mountain Castles of Yamato,” and is known as one of the representative mountain castles of Yamato Province, alongside Toyoda Castle and Kubonosho Castle.
Built on a mountaintop approximately 300 meters above sea level, this castle boasts a diverse array of well-preserved remains, including baileys, earthworks, dry moats, ridged trenches, stone walls, and wells, making it a fascinating historical site for castle enthusiasts and history buffs.
History of Tsubakio Castle
Construction History and Historical Context
Tsubakio Castle is believed to have been built during the Tenbun era (1532-1555). The builder was Tsutsui Junsho, who played a crucial role in the power struggles within Yamato Province during the Sengoku period.
In Yamato Province, the temple and shrine forces centered around Kofuku-ji Temple and local samurai forces such as the Tsutsui and Furuichi clans were intricately intertwined, leading to fierce conflicts. The Tsutsui clan, a powerful local lord in Yamato Province, was based at Tsutsui Castle (Yamato-Koriyama City), but they faced a temporary loss of power due to the invasion of Matsunaga Hisahide.
Tsutsui Junsho and Tsubakio Castle
Tsutsui Junsho was a warrior known as the restorer of the Tsutsui clan. Despite pressure from Matsunaga Hisahide, he continued to resist from Tsubakio Castle. Tsubakio Castle functioned as an outpost for Tsutsui Castle, serving as both an emergency refuge and a base for counterattacks.
Junsho died young in 1550, but his will was carried on by his son, Tsutsui Junkei.
Conflict between Tsutsui Junkei and Matsunaga Hisahide
After Tsutsui Junsho’s death, the young Tsutsui Junkei inherited the family headship. During this period, Matsunaga Hisahide was expanding his power in Yamato Province with the backing of Oda Nobunaga.
In 1559, Tsutsui Castle fell to an attack by Matsunaga Hisahide, and Junkei temporarily lost his base. In this critical situation, Tsubakio Castle became a crucial base for Junkei to launch his counterattack. Junkei continued his resistance from Tsubakio Castle, and eventually, when Oda Nobunaga changed his policy and the Tsutsui clan was appointed as the governor of Yamato Province, he regained his power.
Relationship with Tsubakio-Shimo Castle
Tsubakio Castle consists of two castles: “Tsubakio-Kami Castle” and “Tsubakio-Shimo Castle.”
Tsubakio-Shimo Castle is believed to have been built during the Muromachi period by the local Tsubakio clan. The Tsubakio clan were monks of Daijoin, a sub-temple of Kofuku-ji Temple and a monzeki temple, and served as the local administrators of Hata-sho and Takada-sho. Initially, they were subordinate to the Furuichi clan, but later became subordinate to the Tsutsui clan.
Amidst the intensifying conflict with the Matsunaga clan, Tsubakio-Shimo Castle was renovated and came to function as a subsidiary castle of Tsubakio-Kami Castle. It is believed that the two castles worked together to form a coordinated defensive system.
The Abandoned Castle and its Aftermath
In 1580 (Tensho 8), Tsutsui Junkei moved to Yamato-Koriyama Castle by order of Oda Nobunaga, and it is believed that Tsubakio Castle ceased to serve its purpose. Afterward, the castle was abandoned, and remains of the structure persist in the mountains to this day.
The Layout and Remains of Tsubakio Castle
Castle Structure
Tsubakio Castle is a large mountain castle centered on the mountaintop, extending approximately 200 meters east-west and 150 meters north-south. Multiple baileys are arranged around the main bailey, with each bailey separated and defended by moats and trenches.
To enhance its defensive capabilities as a mountain castle, strong defensive structures were constructed through skillful use of natural terrain and artificial civil engineering.
Main Bailey (Honmaru)
The main bailey, the center of the castle, is located on the mountaintop and is a long, oval-shaped flat area running east-west. Earthen ramparts surround it, further enhancing its defensive capabilities.
Within the main enclosure, the remains of a well have been confirmed, indicating that water supply was considered during sieges. This well remains clearly visible today and is one of the important historical remains.
Enclosures
Several enclosures are arranged in a stepped pattern around the main enclosure. A belt-shaped enclosure is located on the south side, serving both as a movement route within the castle and as a defensive line.
Enclosures also extend to the east and west, creating a structure designed to withstand attacks from multiple directions. Each enclosure is clearly demarcated by earthworks and steep slopes, exhibiting a typical layout for a mountain castle of the Sengoku period.
Moats and Ridge-Shaped Vertical Moats
One of the greatest highlights of Tsubakio Castle is its large-scale moats and ridge-shaped vertical moats.
Deep moats are located on the south and north sides of the main enclosure, forming a defensive line to prevent intrusion from the ridge. The moat on the south side is particularly large, measuring approximately 5 meters deep and 10 meters wide.
The ridged vertical moats are defensive structures dug in parallel on the slopes of castles, effectively hindering enemy lateral movement and dispersing attacks. At Tsubakio Castle, magnificent ridged vertical moats can be seen on the eastern and western slopes. Their scale and excellent state of preservation make them valuable historical remains demonstrating the high level of castle construction technology in Yamato Province.
Horizontal Moats
In some areas, horizontal moats (moats dug horizontally) surround the baileys. These moats made approaching the baileys difficult and enhanced defensive capabilities.
Some horizontal moats are combined with earthworks, forming an even stronger defensive line.
Stone Walls
Partial stone walls remain at Tsubakio Castle. This is a relatively rare feature for a Sengoku period mountain castle, indicating that the use of stone walls in important locations enhanced both defensive strength and imposing appearance.
The stone walls are constructed using the nozura-zumi method, stacking natural stones in a style not as neatly arranged as later castles, but they are valuable resources for understanding the castle-building techniques of the time.
Earthworks
Earthworks surround each enclosure. These earthworks are defensive structures built by piling up earth, preventing enemy intrusion and also serving as cover for defensive fire from within.
The earthworks around the main enclosure are particularly large, reaching heights of approximately 2-3 meters in some places.
Access to Tsubakio Castle
Access by Public Transportation
The following routes are convenient for visiting Tsubakio Castle by public transportation:
Nearest Station: JR Sakurai Line/Kintetsu Tenri Line “Tenri Station”
Bus: From Tenri Station, take the Nara Kotsu bus bound for “Sharp General Development Center/Meihan National Highway (Route 18 or 21)” and get off at the “Kokudo Gokaya” bus stop.
It takes approximately 15-20 minutes to walk from the bus stop to the castle entrance. Since the route goes through a residential area before entering a mountain path, it’s recommended to check your location beforehand using a map or GPS app.
Access by Car
If visiting by car, it’s about 10 minutes from the Tenri-Higashi Interchange on the Meihan Expressway. However, there is no dedicated parking lot around the castle ruins, so please be careful not to park on the street.
If using nearby vacant spaces or public facility parking lots, be sure to obtain permission or choose an appropriate location.
Castle Ascent Route
The most common route to the castle is from the north side. Entering the mountain path from the back of the residential area, you can reach the main enclosure in about 20-30 minutes of hiking.
The castle trail is an unmaintained natural path, so appropriate clothing and shoes for hiking are necessary. Be especially careful after rain, as it can become slippery.
There is also a route that passes through the remains of Tsubakio-Shimo Castle, allowing you to visit both castles.
Highlights and Points to Note When Visiting Tsubakio Castle
Value as One of the Three Great Mountain Castles of Yamato
Tsubakio Castle, along with Toyoda Castle and Kubonosho Castle, is a renowned castle counted among the “Three Great Mountain Castles of Yamato.” These mountain castles are highly valued by castle researchers and enthusiasts as valuable historical sites that convey the castle-building techniques and historical background of the Sengoku period in Yamato Province.
The “Yamato Three Great Mountain Castles Tour,” visiting all three castles, is a popular route for mountain castle fans in Nara Prefecture.
Preservation of the Remains
The remains of Tsubakio Castle remain remarkably well-preserved, even more than 400 years after its abandonment. The scale and state of preservation of the ridged vertical moats are particularly impressive, offering a valuable opportunity to experience the defensive system of a Sengoku period mountain castle.
Remains such as moats, earthworks, and baileys can also be clearly seen, allowing visitors to stroll around while imagining the castle’s appearance at the time.
Harmony with the Natural Environment
Tsubakio Castle stands quietly amidst the forest, offering a beautiful landscape where the natural environment and historical remains harmonize. You can enjoy exploring the castle ruins amidst the changing scenery of the seasons, from fresh greenery in spring to vibrant autumn foliage.
However, in summer, the vegetation can make the ruins difficult to see, so spring or autumn are recommended for your visit.
Precautions When Visiting
Please note the following points when visiting Tsubakio Castle:
- Hiking Equipment: Prepare hiking boots, long-sleeved shirt and long pants, a hat, and drinking water.
- Insect Protection: Mosquito and bee repellent is necessary in summer.
- Avoid Solo Visits: Visiting with multiple people is safer if possible.
- Mobile Phone: Carry a mobile phone for emergency contact.
- Take Your Trash Home: For the protection of the natural environment, be sure to take all your trash with you.
Please understand that the castle ruins are not a developed tourist attraction, but rather a historical site in the middle of a forest. Visit at your own risk.
Related Historical Sites Around Tsubakio Castle
Tsubakio Shimo Castle
Tsubakio Shimo Castle, which functioned as a subsidiary castle of Tsubakio Kami Castle, is another historical site worth visiting when you come to Tsubakio Castle. Although covered with bamboo groves and trees, the remains of the baileys, earthworks, dry moats, and trenches are well-preserved.
Visiting it together with Tsubakio Kami Castle will give you a deeper understanding of the Tsutsui clan’s defensive system.
Tsutsui Castle Ruins
The Tsutsui Castle Ruins (Yamato-Koriyama City), the base of the Tsutsui clan, are also a historical site closely related to Tsubakio Castle. Although it is now a residential area and very few remains are left, it is an important place for understanding the history of the Tsutsui clan.
The history of this castle, which served as the residence of Tsutsui Junkei and became the center of Yamato Province’s rule, is deeply intertwined with the origins of Tsubakio Castle.
Koriyama Castle
Koriyama Castle (Yamato Koriyama Castle), where Tsutsui Junkei moved in 1580, is a historical site with well-preserved remains such as stone walls and moats. It’s not far from Tsubakio Castle, so visiting both together will provide a more comprehensive understanding of the Tsutsui clan’s history.
Historical Significance of Tsubakio Castle
A Castle that Tells the Story of the Political Situation in Sengoku Yamato
Tsubakio Castle is a castle that symbolizes the complex political situation in Yamato Province during the Sengoku period. Amidst the intertwining forces of various powers—the temple and shrine powers centered around Kofuku-ji Temple, the local Tsutsui clan, the invader Matsunaga Hisahide, and the central government under Oda Nobunaga—Tsubakio Castle became a base for the Tsutsui clan’s survival.
The history of this castle is not merely the history of a local castle, but an important case study for understanding the power structure and regional governance of the Sengoku period.
The Pinnacle of Mountain Castle Construction Technology
The layout and remains of Tsubakio Castle represent the pinnacle of mountain castle construction technology in the late Sengoku period. Features such as ridged vertical moats, large-scale trenches, and complex bailey arrangements demonstrate ingenious methods for effectively defending against enemy attacks.
These techniques represent the latest castle construction methods adopted by Sengoku daimyo throughout Japan, and provide evidence of their influence in Yamato Province.
Important Resource for Regional History Research
Tsubakio Castle holds an important position in the study of regional history in Nara Prefecture. This is because the physical evidence of the remains provides clues to understanding the actual conditions of the time, which cannot be known from documentary sources alone.
Further information is expected to be revealed through future archaeological excavations and detailed surveys.
Summary
Tsubakio Castle (Tsubakioue Castle) is a Sengoku period mountain castle located in Kita-Tsubakio-cho, Nara City, Nara Prefecture. It is a historically significant fortress, serving as a base for Tsutsui Junsho and his son Junkei during their conflict with Matsunaga Hisahide.
As one of the three great mountain castles of Yamato Province, this castle boasts a variety of well-preserved remains, including ridged trenches, moats, earthworks, and stone walls, making it a valuable historical site that conveys the appearance of a Sengoku period mountain castle to the present day.
While access by public transportation is somewhat inconvenient, it is a magnificent castle well worth visiting for castle enthusiasts and history buffs. Prepare your hiking gear, be mindful of the natural environment, and enjoy exploring the castle ruins and feeling the spirit of the Sengoku period.
A visit to Tsubakio Castle will provide a valuable experience that allows you to reflect on the history of the Sengoku period in Yamato Province and the struggles of the Tsutsui clan.
