Akami Castle (Sano City, Tochigi Prefecture) Complete Guide: History and Highlights of a Flatland Castle with Remaining Double Earthworks and Moats
Introduction
Akami Castle is a flatland castle site located in Akami-cho, Sano City, Tochigi Prefecture. While currently used as Akami Castle Nursery School, it is a valuable historical site with well-preserved remains of a medieval castle. It boasts a vast castle area spanning approximately 450 meters east-west and 360 meters north-south, and the remains of the double earthworks and moats, in particular, represent an astonishing amount of earthwork for a flatland castle.
This article thoroughly explains the charm of Akami Castle, including its history, the changes in its lords, the characteristics of its layout, the remains that can be seen on-site, and how to access it.
History of Akami Castle
Construction and the Akami Clan
There are various theories regarding the construction of Akami Castle, but one theory suggests it was built in 1178 (Jisho 2) at the end of the Heian period by Ashikaga Toshitsuna. Subsequently, the Akami clan, who ruled this area, developed and expanded the castle as their residence.
As a powerful vassal of the Sano clan, the Akami clan played an important role in the Sano clan’s control of their territory, which was based at Karasawayama Castle. Located midway between Karasawayama Castle and Ashikaga Castle, which belonged to the Ashikaga Nagao clan, Akami Castle functioned as a crucial strategic point for the defense of the Sano territory.
The Eiroku Rebellion and Change of Lord
The most important turning point in the history of Akami Castle was the incident of Eiroku 2 (1559). Akami Iga-no-kami, the lord of the castle at the time, rebelled against his lord, Sano Yasutsuna. It is believed that this rebellion was rooted in internal power struggles within the Sano clan and the complexities of the Sengoku period in the Kanto region.
As a result, Akami Iga-no-kami was driven out of the castle by Sano Yasutsuna, and Akami Castle became a directly controlled branch castle of the Sano clan. From then on, the castle served as a subsidiary castle of Karasawayama Castle and Sano Castle, playing a vital role in the Sano clan’s territorial defense system. Records indicate that during this period, Sano clan retainers such as Togasaki Yoshimune were stationed as castle guards.
Sano Clan’s Dispossession and Castle Abandonment
The history of Akami Castle comes to an end in the early Edo period. In 1614 (Keicho 19), when the Sano clan was dispossessed of their domain, Akami Castle, their subsidiary castle, was also abandoned. This dispossession of the Sano clan was part of the Edo shogunate’s control over daimyo, and many Sengoku daimyo in the Kanto region suffered the fate of dispossession or relocation during this period.
After the castle’s abandonment, the site was used for farmland and residential areas. Fortunately, the main remains escaped destruction and have been preserved in good condition to this day.
Layout and Structure of Akami Castle
Castle Size and Layout
Akami Castle is a vast flatland castle measuring approximately 450 meters east-west and 360 meters north-south. Multiple baileys (enclosures) were arranged, creating a defensive system centered around the main keep.
The current Akami Castle Nursery School is located on the site of the main keep, and it has been confirmed that multiple baileys, including a northern and southern enclosure, were arranged around it. The sheer scale of this flatland castle speaks volumes about its importance as a base for the Sano clan.
Features of the Double Earthen Embankment
The most striking feature of Akami Castle is the double earthen embankment remaining on the west and northwest sides. In addition to the inner embankment surrounding the main keep, another embankment was built outside of it, forming a double defensive line.
The height of the embankment varies depending on the location, but in well-preserved sections, it maintains a height of approximately 3-4 meters. This is a considerably high embankment for a flatland castle, demonstrating the advanced civil engineering techniques of the time of its construction. The double earthen ramparts on the west side are particularly impressive, offering an enjoyable walk along them.
Moat System
Akami Castle is surrounded by moats on three sides—east, west, and north—excluding the south. On the west and northwest sides, where the double earthen ramparts are located, moats also surround the outside of the ramparts, confirming the double moat structure.
It is believed that the moats in this flatland castle served not only a defensive function but also provided irrigation water for the surrounding rice paddies. Even today, some of the moats still contain water, allowing us to imagine their former appearance. The moats are over 10 meters wide in some places, indicating a large-scale moat system for a flatland castle.
Main Enclosure and Surrounding Baileys
The main enclosure is currently used as Akami Castle Nursery School, so detailed internal investigations are limited. However, based on the arrangement of the surrounding earthen ramparts, it is estimated to have been approximately 100 meters east-west and 80 meters north-south.
To the north and south of the main enclosure were enclosures corresponding to the second and third baileys, each demarcated by earthworks and moats. These enclosures are thought to have been used as living spaces, warehouses, and training grounds.
Highlights of Akami Castle
Well-Preserved Earthworks
The greatest highlight of Akami Castle is undoubtedly its well-preserved earthworks. The earthworks surrounding the east, west, and north sides of the main enclosure are particularly impressive in their height.
There are also sections where you can walk along the top of the earthworks (earthwork walk), allowing you to experience the castle’s defensive system. The view of the moats and surrounding landscape from atop the earthworks will be a valuable experience for understanding the defenses of castles during the Sengoku period.
Remains of the Double Moat
The double moat on the west side is the core of Akami Castle’s defensive system. Earthworks were built between the inner and outer moats, forming a double defensive line. This structure was a clever design to prevent enemy incursions in stages, demonstrating the advanced defensive technology of medieval castles.
Remains of the Double Moat At the site, the remains are arranged around the nursery school grounds, allowing visitors to observe the double moat while walking around the perimeter of the school. The relationship between the double earthworks and the double moat is particularly clear near the northwest corner.
Scale of Civil Engineering for a Flatland Castle
Akami Castle, despite being a flatland castle, underwent large-scale civil engineering work comparable to that of a mountain castle. This was necessary to create artificial elevation differences using earthworks and moats to enhance its defensive capabilities on flat ground.
The sheer volume of earth moved during construction speaks to the high level of labor mobilization and technological capabilities of the time. Such large-scale civil engineering was made possible by the economic power of the Sano clan and the strategic importance of Akami Castle.
Coexistence with Modern Times
The Akami Castle site is currently used as Akami Castle Nursery School, a rare example of historical heritage coexisting with modern facilities. Visitors can explore the remains around the perimeter while respecting the nursery school’s operations.
This characteristic of being an “actively used castle site” is attracting attention as a model case for the preservation and utilization of castle ruins. The way the castle site continues to thrive within the local community is invaluable as a bridge between history and the present.
Akami Castle and the Sano Clan’s Castle Network
Relationship with Karasawayama Castle
Akami Castle was an important branch castle of Karasawayama Castle, the main castle of the Sano clan. Karasawayama Castle is a mountain castle built on Karasawayama Mountain, 247 meters above sea level, and is known as one of the strongest castles in the Kanto region.
Akami Castle is located approximately 7 kilometers southeast of Karasawayama Castle and served as a forward base on the plains. Karasawayama Castle, a mountain castle, and Akami Castle, a flatland castle, had a complementary relationship, utilizing their respective topographical characteristics.
Positional Relationship with Ashikaga Castle
Another important strategic position of Akami Castle is its location midway between it and Ashikaga Castle, the Ashikaga Nagao clan’s castle. Ashikaga Castle is located approximately 10 kilometers northeast of Akami Castle, and the Sano and Ashikaga Nagao clans were in a long-standing conflict.
Due to this geographical location, Akami Castle functioned as a defensive base for the northeastern part of the Sano territory and as a base for advancing towards the Ashikaga area. The rebellion of Akami Iga-no-kami during the Eiroku era is thought to have occurred amidst this tension.
Coordination with Sano Castle
Sano Castle was a flatland castle used as the Sano clan’s residence during peacetime, located at the foot of Karasawayama Castle. After Akami Iga-no-kami’s rebellion, Akami Castle was positioned as a subsidiary castle of both Karasawayama Castle and Sano Castle, forming a coordinated defensive system involving the three castles.
This kind of defensive network combining multiple castles is a typical pattern in the territorial control of Sengoku daimyo, and it shows that the Sano clan also arranged their castles in accordance with the trends of the time.
Access and Visiting Guide
Location
Address: Akami-cho, Sano City, Tochigi Prefecture
Akami Castle Ruins are located in Akami-cho, approximately 5 kilometers southeast of the center of Sano City. Currently, the site is occupied by Akami Castle Nursery School, and remnants of the castle remain around the nursery school.
Access
By Train:
- Approximately 10 minutes by car from JR Ryomo Line/Tobu Sano Line “Sano Station”
- Taking a taxi from Sano Station is convenient
- Bus service is limited, so please check the timetable in advance.
By Car:
- Approximately 15 minutes from Kita-Kanto Expressway “Sano-Tanuma IC”
- Approximately 20 minutes from Tohoku Expressway “Sano-Fujioka IC”
- Please be considerate of the nursery school’s operation and avoid street parking; use nearby public facilities.
Visitor Etiquette
Akami Castle Ruins are currently used as a nursery school, so please observe the following points when visiting:
- Do not enter the nursery school grounds: The main keep area is part of the nursery school grounds, so entry inside is prohibited.
- Be quiet: During nursery hours, please be considerate of the children’s activities and refrain from raising your voice.
- Photography: Please be careful not to include the nursery school building or children in your photos.
- Walking the Earthen Embankment: When walking on the earthen embankment, please act carefully to avoid damaging the remains.
- Take Your Trash Home: Please be sure to take your trash home with you after your visit.
Estimated Visit Time
To visit the Akami Castle ruins, please allow approximately 30 minutes to 1 hour if you walk around the outer earthen embankment and moat. If you want to carefully observe the remains or enjoy taking photographs, it would be best to allow about 1.5 hours.
Best Season
While Akami Castle Ruins are open year-round, the following seasons are recommended:
- Spring (March-May): The season of fresh greenery, when the vegetation on the earthworks is at its most beautiful.
- Autumn (October-November): The combination of autumn leaves and the castle ruins is stunning, and the weather is ideal for visiting.
- Winter (December-February): The vegetation withers, making it easier to observe the structure of the remains.
In summer, the vegetation can be overgrown, making the remains difficult to see. Also, be careful as the earthworks can become slippery in rainy weather.
Nearby Tourist Attractions
Karasawayama Castle Ruins
If you visit Akami Castle, be sure to also visit Karasawayama Castle Ruins, the main castle of the Sano clan. It is a nationally designated historical site and is known as one of the most impressive mountain castles in the Kanto region with well-preserved stone walls. The view from the summit is magnificent, offering a panoramic view of the Kanto Plain.
Sano Castle Ruins
The Sano Castle Ruins, located in the city of Sano, are a historical site worth visiting along with Akami Castle. Currently, it is maintained as a park, and parts of the earthworks and moats remain.
Sano City Local History Museum
This museum allows you to learn about the history and culture of Sano City. It also displays materials related to the Sano clan and Akami Castle, and visiting before or after visiting the castle ruins will deepen your understanding.
Izuruhara Benten Pond
This spring-fed pond is known as one of Sano City’s famous water sources and has been selected as one of the “100 Best Waters” by the Ministry of the Environment. It is about a 15-minute drive from Akami Castle, making it ideal for a stop during your sightseeing.
Cultural Property Designation Status of Akami Castle
While the Akami Castle Ruins are recognized as a historical site of Sano City, they are not designated as a national or prefectural cultural property. However, due to the well-preserved remains, preservation efforts are underway to preserve it as a valuable historical heritage of the region.
Izuruhara Benten Pond
This spring-fed pond is known as one of Sano City’s famous water sources and has been selected as one of the “100 Best Waters” by the Ministry of the Environment. It is approximately a 15-minute drive from Akami Castle, making it an ideal stop during your sightseeing.
Cultural Property Designation Status of Akami Castle
The Akami Castle Ruins are recognized as a historical site of Sano City, but they are not designated as a national or prefectural cultural property. However, because the remains are well-preserved, preservation efforts are being made as a valuable local historical heritage site. In recent years, with the growing interest in medieval castles, the remains of flatland castles like Akami Castle are being re-evaluated. It is hoped that more proactive preservation and utilization measures will be considered in the future.
The Value of Akami Castle in Castle Research
A Fine Example in Flatland Castle Research
Akami Castle is an extremely important example for understanding the structure of flatland castles. Unlike mountain castles, castles built on flat land could not utilize the natural terrain, making the construction of artificial defensive structures essential.
Akami Castle’s double earthworks and double moats demonstrate a typical method of strengthening the defensive capabilities of a flatland castle, making it valuable material for studying castle construction techniques of the Sengoku period.
Contribution to Sano Clan Research
Research on Akami Castle is also important for understanding the territorial control system of the Sengoku daimyo Sano clan. Multifaceted research is possible, including the hierarchical castle layout (main castle, branch castles, and outposts), the arrangement of retainers, and the territorial defense strategy.
The Akami Iga-no-kami rebellion of 1559 (Eiroku 2) is a particularly interesting case study for understanding the political history of the Sengoku period, as it reveals the relationship between Sengoku daimyo and their retainers, and the power struggles within those retainers.
A Model Case for Preservation and Utilization
Akami Castle, where the remains are preserved while the site is used as a modern facility (a nursery school), can serve as a model case for considering the balance between preservation and utilization of castle ruins.
The approach of utilizing historical heritage as “living heritage” within the local community, rather than isolating it as “relics of the past,” is an important perspective for future cultural property protection policies.
How to Enjoy Your Visit to Akami Castle
Points to Observe the Ruins
- Western Double Earthwork: This is the best-preserved section, allowing you to truly appreciate the double defensive system.
- Northwest Corner: This is the clearest place to observe the relationship between the double earthwork and the double moat.
- Eastern Earthwork: The earthwork on the east side of the main enclosure is high, allowing you to experience the difference in elevation with the moat.
- Water Moat: There are still areas where water remains, making it easy to imagine its appearance in the past.
Photography Tips
- Wide-Angle Lens: A wide-angle lens is effective for capturing the scale of the earthwork.
- Morning and Evening Light: Oblique light emphasizes the undulations of the earthwork, resulting in photos with a sense of depth.
- Seasonal Atmosphere: The seasons of fresh greenery and autumn leaves produce beautiful photos of the harmony between nature and the ruins.
- Considerations: Please be careful not to include the nursery school building or children in your photos.
Historical Walking Tour Course
A Tour of Sano Clan Castles, Including Akami Castle:
- Morning: Karasawayama Castle Ruins (2-3 hours)
- Lunch: Sano Ramen in Sano City
- Afternoon: Sano City Local History Museum (1 hour)
- Afternoon: Akami Castle Ruins (1 hour)
- Evening: Izuruhara Benten Pond (30 minutes)
This course allows you to experience the Sano clan’s castle system in one day.
Summary
Akami Castle (Sano City, Tochigi Prefecture) is a valuable flatland castle ruin with well-preserved double earthworks and moats. It played an important role as the residence of the Akami clan, vassals of the Sano clan, and as a key point in the defense of Karasawayama Castle.
The historical changes of Akami Castle—from the rebellion of Akami Iga-no-kami in 1559, to its subsequent direct control as a branch castle of the Sano clan, and finally its abandonment in 1614 following the Sano clan’s downfall—symbolize the fate of local samurai groups during the transition from the Sengoku period to the Edo period.
Although currently used as Akami Castle Nursery School, the remains of the castle, including high earthworks on the east, west, and north sides, double earthworks, and a moat, are preserved, boasting an astonishing amount of earthwork for a flatland castle. Visitors can explore the outer perimeter remains while respecting the nursery school’s operations.
When visiting Sano City in Tochigi Prefecture, be sure to visit Akami Castle along with Karasawayama Castle and Sano Castle. You’ll find many discoveries from both the perspectives of Sengoku period castle defense systems and the modern use of historical heritage.
Akami Castle will continue to be a valuable cultural asset of Sano City, a “living heritage” that conveys the region’s history to the present day.
