Tsurumine Castle (Inawashiro Town, Fukushima Prefecture) Complete Guide | Thorough Explanation of History, Remains, and Access
Tsurumine Castle, located in Inawashiro Town, Fukushima Prefecture, is a castle that marked a significant historical turning point in the Aizu region at the end of the Sengoku period. Known as the retirement castle of Inawashiro Morikuni, it is a noteworthy presence in the history of the Sengoku period in the Tohoku region, as it was the stage that triggered the downfall of the Ashina clan. This article will introduce the charm of this castle ruin in its entirety, from its detailed history and existing remains to a visitor’s guide and surrounding tourist information.
What is Tsurumine Castle? | Basic Information and Overview
Tsurumine Castle is a medieval mountain castle located in Inawashiro Town, Yama District, Fukushima Prefecture. Built on a hillside overlooking the Aizu Basin, north of Lake Inawashiro, it functioned as a subsidiary castle of Inawashiro Castle.
Basic Castle Data
- Location: Inawashiro-machi, Yama-gun, Fukushima Prefecture
- Other Names: None (Known as Tsurumine Castle)
- Castle Structure: Mountain Castle
- Construction Period: Late 16th Century (Estimated)
- Builder: Inawashiro Morikuni
- Main Lord: Inawashiro Morikuni
- Year of Abandonment: 1590 (Tensho 18)
- Remains: Earthworks, dry moats, stone walls, bailey remains
- Designated Cultural Property: Not Designated
Tsurumine Castle, unlike the main castle Inawashiro Castle, is believed to have served as a retirement castle. Although small in scale, it was strategically located and played an important role in the history of the Aizu region.
The History of Tsurumine Castle | Inawashiro Morikuni and the Path to the Downfall of the Ashina Clan
The Genealogy of Inawashiro Morikuni and the Inawashiro Clan
The Inawashiro clan was a samurai family that ruled the Inawashiro region, as a branch of the prestigious Ashina clan of Aizu. Inawashiro Morikuni served the Ashina clan for many years as a senior retainer. Based at Inawashiro Castle, he contributed to maintaining the Ashina clan’s power in the northern part of Aizu.
In his later years, Morikuni handed over the family headship to his eldest son, Inawashiro Moritane, and retired. It is believed that Tsurumine Castle was built or renovated at this time. Given its nature as a retirement castle, it is possible that livability and good views were prioritized over its defensive function.
The Betrayal of 1588 | A Turning Point in History
The name of Tsurumine Castle was etched into history in 1588. In that year, Inawashiro Morikuni made a decision that would drastically change the history of the Tohoku region.
While his eldest son, Inawashiro Moritane, was away, Morikuni seized Inawashiro Castle by force and defected to Date Masamune, taking the castle with him. This betrayal was a fatal blow to the Ashina clan, which was in decline at the time.
Background of the Defection
Several factors can be considered as the background to Morikuni’s defection to Date Masamune.
- Decline of the Ashina Clan: Due to the lack of governing ability of the head of the clan, Ashina Yoshihiro (adopted from the Satake clan), the Ashina clan’s power had weakened.
- The Rise of Date Masamune: The young and ambitious Date Masamune was rapidly expanding his power and was on the verge of becoming the ruler of the Tohoku region.
- The Succession Problem: It has been suggested that there may have been some kind of conflict between Morikuni and his eldest son, Moritane.
- Strategic Judgment: After calmly analyzing the situation in the Aizu region, it is possible that Morikuni judged that siding with the Date clan would be advantageous for the survival of the Inawashiro clan.
The Battle of Suriagehara and the Downfall of the Ashina Clan
Morikuni’s defection led to the Battle of Suriagehara in the following year, Tensho 17 (1589). Having lost Inawashiro Castle, a strategic stronghold in northern Aizu, the Ashina clan was forced into a strategically disadvantageous position.
In the Battle of Suriagehara, Date Masamune defeated Ashina Yoshihiro, effectively ending the Ashina clan. The Aizu region came under the control of the Date clan, and Inawashiro Morikuni’s betrayal became a crucial turning point in this historical transition.
The Oshu Settlement and the Abandonment of Tsurumine Castle
In 1590 (Tensho 18), Toyotomi Hideyoshi implemented the “Oshu Settlement.” This was a policy by the Toyotomi regime to reorganize the distribution of daimyo in the Tohoku region.
As a result of this Oshu Settlement, Date Masamune was ordered to withdraw from the Aizu region and transferred to Yonezawa. Inawashiro Morikuni also left Aizu following the Date clan, and Tsurumine Castle was abandoned.
The period during which Tsurumine Castle was actually used was relatively short, believed to be only a few years from Morikuni’s retirement until the Oshu Settlement. However, during that short period, it became a stage for major changes in the history of the Tohoku region.
Structure and Layout of Tsurumine Castle
Location and Topographical Characteristics
Tsurumine Castle was built on a hilly area that spreads out north of Lake Inawashiro. This location offered the following strategic advantages:
- Excellent Views: Its location offered a panoramic view of the Aizu Basin and Lake Inawashiro, making it easy to monitor surrounding movements.
- Defensiveness: It utilized the hilly terrain to create a natural stronghold.
- Coordination with Inawashiro Castle: Its moderate distance from the main castle, Inawashiro Castle, allowed it to function as a subsidiary castle.
Given its nature as a retirement castle, it is presumed to have been designed with a balance between habitability and defense, rather than being a large-scale military facility.
Components of the Castle
The remains of Tsurumine Castle reveal a typical structure for a medieval mountain castle.
Kuruwa (Enclosure)
This was the flat area at the center of the castle where buildings were constructed. At Tsurumine Castle, it is believed that multiple enclosures were arranged around the main enclosure. While not large in scale, it was spacious enough for a retirement castle.
Dorui (Earthwork)
One of the remains that can still be clearly identified today is the dorui (earthwork). These are defensive structures built by piling up earth, arranged to surround the baileys. The earthworks of Tsurumine Castle remain in relatively good condition, making them valuable resources for understanding the castle’s structure at the time.
Dry Moat
A moat without water, a defensive structure designed to prevent enemy intrusion. At Tsurumine Castle, dry moats were constructed between baileys or along the outer edges of the castle grounds. The shape of the moats can still be seen in some areas today.
Stone Wall
A defensive structure built by stacking stones. Traces of stone walls have been partially confirmed at Tsurumine Castle. It is thought that the stones were used to reinforce the earthworks rather than forming complete stone walls.
Characteristics of the Castle Layout
The layout (design and arrangement) of Tsurumine Castle exhibits typical characteristics of mountain castles in the Tohoku region from the late 16th century.
- Continuous Enclosure Structure: A style in which enclosures are arranged in a continuous sequence.
- Utilization of Natural Terrain: A design that skillfully utilizes the undulations of the hills.
- Compact Scale: Not a castle for stationing a large army, but a suitable size for a retirement castle.
Highlights of Tsurumine Castle | Existing Remains
Preservation of Earthworks and Dry Moats
The biggest highlight when visiting Tsurumine Castle is the well-preserved earthworks and dry moats. Although more than 400 years have passed since the castle was abandoned, the destruction of the remains has been minimized because the area has been protected as a forest.
In particular, the earthworks around the main enclosure remain relatively clear in height and shape, allowing you to experience the castle structure of the time. Although parts of the dry moats have been filled in, there are places where you can experience their depth and width by walking along the bottom of the moat.
Traces of Stone Walls
The partially remaining stone walls are valuable remains for understanding the construction techniques of Tsurumine Castle. While not a complete stone wall, the use of stone in the base of the earthworks and in important areas offers a glimpse into the castle-building techniques of the Aizu region in the late 16th century.
Stunning Views
The views from Tsurumine Castle Ruins are a major attraction for visitors. On a clear day, you can see the beautiful surface of Lake Inawashiro, the expansive Aizu Basin, and the majestic Mount Bandai in the distance.
This view is not merely aesthetically pleasing, but also helps to understand how strategically important this castle was during the Sengoku period.
Atmosphere as a Historical Stage
Beyond the ruins themselves, Tsurumine Castle Ruins possesses a unique atmosphere as a stage for the history of the Sengoku period. Strolling through the site while imagining what Inawashiro Morikuni thought and what decisions he made here deepens your understanding of history.
Visitor Guide | Access and Visiting Information for Tsurumine Castle
Access Methods
Access by Car
The most convenient way to access Tsurumine Castle Ruins is by car.
From the Ban-etsu Expressway
- Approximately 15 minutes by car from the Inawashiro Bandai Kogen Interchange on the Ban-etsu Expressway
- Via National Route 49 towards the center of Inawashiro Town
From Fukushima City
- Approximately 45 minutes via National Route 115
From Aizuwakamatsu City
- Approximately 20 minutes via National Route 49
Access by Public Transportation
Using the JR Ban-etsu West Line
- Get off at JR Inawashiro Station
- Approximately 10 minutes by taxi or 40 minutes on foot from the station
*If using public transportation, we recommend taking a taxi due to the distance from the station.
Parking Information
There is no dedicated parking lot at Tsurumine Castle Ruins. You will need to park in a suitable nearby location, but we recommend checking the latest information at the Inawashiro Town Tourist Information Center before your visit.
Important Notes for Visitors
Clothing and Equipment
- Comfortable walking shoes: Trekking shoes or athletic shoes are essential as it is a mountain castle site.
- Long-sleeved shirt and long pants: To protect yourself from vegetation and insects.
- Hat: For sun protection.
- Drinking water: Especially essential in summer.
Seasonal Precautions
- Spring and Autumn: The best seasons for visiting. The weather is mild and it is easy to observe the ruins.
- Summer: Vegetation can grow thickly, making it difficult to see the ruins. Insect repellent is also necessary.
- Winter: Snowfall may make visiting difficult.
Safety Precautions
- As it is a mountain castle site, there are areas with unstable footing.
- Visiting in a group is safer than visiting alone.
- It is recommended to check the cell phone signal strength in advance.
Estimated Visiting Time
Please allow the following time as a guideline for visiting Tsurumine Castle Ruins.
- Short Visit: 30 minutes to 1 hour
- In-depth Visit: 1 to 2 hours
- Photography and Detailed Observation: 2 hours or more
Nearby Tourist Attractions and Landmarks
When visiting Tsurumine Castle, visiting nearby tourist attractions will make your trip even more fulfilling.
Inawashiro Castle Ruins
The ruins of Inawashiro Castle, the main castle of Tsurumine Castle, are also a must-visit spot. Also known as Kamega Castle, this castle is an important historical site where Inawashiro Morikuni defected to Date Masamune.
- Location: Kojōmachi, Inawashiro-machi, Yama-gun, Fukushima Prefecture
- Distance from Tsurumine Castle: Approximately 10 minutes by car
- Highlights: Stone walls, earthworks, moat remains, etc.
Lake Inawashiro
Lake Inawashiro, the fourth largest lake in Japan, is a representative tourist attraction of Fukushima Prefecture. It is a beautiful lake with high transparency, also known as “Tenkyōko” (Heavenly Mirror Lake).
- Distance from Tsurumine Castle: Approximately 15 minutes by car
- Things to do: Lakeside drives, sightseeing boats, water sports, etc.
Aizu-Wakamatsu City (Tsuruga Castle)
Aizu-Wakamatsu City, the central city of the Aizu region, is home to the famous castle “Tsuruga Castle” (Aizu-Wakamatsu Castle). Famous as the site of the Boshin War, its restored keep is now a popular tourist attraction.
- Distance from Tsurumine Castle: Approximately 25 minutes by car
- Highlights: Keep, stone walls, gardens, museum, etc.
*When searching, it is convenient to use the keyword “Tsuruga Castle Aizu-Wakamatsu”. Please note that this is a different castle from Tsurumine Castle, so do not confuse them.
Mount Bandai
Mount Bandai, one of Japan’s 100 Famous Mountains, is a symbolic landmark of Inawashiro Town. Besides mountain climbing, there are numerous hot springs and ski resorts in the surrounding area.
- Distance from Tsurumine Castle: Approximately 20 minutes by car to the trailhead
- Things to do: Hiking, hot springs, skiing, autumn leaf viewing, etc.
Hideyo Noguchi Memorial Museum
This memorial museum preserves and opens to the public the birthplace of Hideyo Noguchi, a world-renowned bacteriologist from Inawashiro Town.
- Location: 81 Mitsuwa Maeda, Inawashiro-machi, Yama-gun, Fukushima Prefecture
- Distance from Tsurumine Castle: Approximately 15 minutes by car
- Highlights: Birthplace, exhibits, hands-on activities, etc.
To learn more about the history of Tsurumine Castle and Aizu
Related historical events
Knowledge of the following historical events is helpful in understanding the history of Tsurumine Castle.
Battle of Suriagehara (1589)
This was a decisive battle between Date Masamune and Ashina Yoshihiro, triggered by the defection of Inawashiro Morikuni. In this battle, the Ashina clan was destroyed, and Aizu came under the control of the Date clan.
Oshu Settlement (1590)
This was a reorganization of the daimyo’s positions in the Tohoku region by Toyotomi Hideyoshi. As a result of this policy, Date Masamune withdrew from Aizu, and Tsurumine Castle was abandoned.
Related Figures
Inawashiro Morikuni
The lord of Tsurumine Castle, a warrior who defected from the Ashina clan to the Date clan. His decision significantly altered the history of Aizu.
Inawashiro Moritane
Morikuni’s eldest son, a figure in a complicated position due to his father’s betrayal.
Date Masamune
A leading Sengoku daimyo of the Tohoku region, he accepted Inawashiro Morikuni’s defection and gained control of Aizu.
Ashina Yoshihiro
The last head of the Ashina clan, he lost Aizu after being defeated in the Battle of Suriagehara.
Recommended Books and Materials
For those who wish to learn more about Tsurumine Castle and the history of Aizu, the following materials are recommended:
- Books on the Sengoku period history of the Aizu region
- Biographies and research books on Date Masamune
- Specialized books on castles in Fukushima Prefecture
- Local history materials of Inawashiro Town
More detailed local historical materials may be available at local libraries and museums.
Preservation and Future of Tsurumine Castle
Current Preservation Status
While Tsurumine Castle ruins are not currently designated as a national or prefectural cultural property, their value is recognized by local history enthusiasts and researchers.
The fact that the area has been preserved as a forest has, in effect, helped preserve the remains and prevented destruction by development. However, without proper management, the remains may be lost due to natural erosion and changes in vegetation.
Future Challenges
The following challenges exist in preserving and utilizing the Tsurumine Castle ruins:
- Investigation and Recording of Remains: Creation of academic records through detailed surveys and excavations
- Maintenance and Public Access: Development of an environment where visitors can safely view the site
- Information Dissemination: Efforts to widely communicate the historical value of Tsurumine Castle
- Collaboration with the Local Community: Preservation activities in cooperation with the local community
Value as a Historical Heritage Site
Although not large in scale, Tsurumine Castle was the stage for an important turning point in the Sengoku period history of the Tohoku region. The fact that Inawashiro Morikuni’s decision changed the history of Aizu gives this castle site special historical value.
Summary | The Significance of Visiting Tsurumine Castle
Tsurumine Castle in Inawashiro Town, Fukushima Prefecture, may at first glance seem like nothing more than a small mountain castle ruin. However, understanding its historical background reveals the significant role this castle played in the history of the Tohoku region.
The decisions made by Inawashiro Morikuni in this area led to the downfall of the Ashina clan and the historical turning point of Date Masamune’s expansion into Aizu. Tsurumine Castle, the stage for these events, is a valuable historical site that conveys the human drama of the Sengoku period and a major turning point in history.
When visiting the Aizu region, be sure to visit Tsurumine Castle in addition to the famous Tsuruga Castle (Aizu-Wakamatsu Castle). Gazing at the earthworks and dry moats remaining in the quiet mountains, and reflecting on the history of over 400 years ago, will surely be an unforgettable experience.
Tsurumine Castle, where you can feel the rich history and nature of Fukushima Prefecture. Please see its charm for yourself.
