Furumiya Castle: Takeda Shingen’s Masterpiece of Earthen Castles | Highlights and History of the Continued Top 100 Japanese Castles
Furumiya Castle (Furumiya Castle Ruins) is a Sengoku period hilltop castle located in Tsukude-Kiyotake, Shinshiro City, Aichi Prefecture. Built as a base for Takeda Shingen’s invasion of Mikawa Province, it is known for the layout design by the renowned general Baba Nobuharu. Even today, the remains of earthworks and vertical moats remain in excellent condition, and it is considered a valuable historical site, sometimes called the “pinnacle of earthen” castles.” It was selected as one of the Continued Top 100 Japanese Castles (No. 150) on April 6, 2017.
History of Furumiya Castle
Background of Construction and Takeda Shingen’s Invasion of Mikawa
The construction of Furumiya Castle was rooted in Takeda Shingen’s strategy to expand his power into the Tokai region. In 1570, during the first year of the Genki era, the Okudaira clan, local lords who ruled the Tsukude region, switched their allegiance from the Tokugawa to the Takeda clan due to Takeda Shingen’s invasion.
Around 1571-1572, Takeda Shingen ordered the construction of Furumiya Castle as a base for his invasion of Mikawa Province. The castle’s layout was designed by Baba Nobuharu (Baba Mino-no-kami Nobuharu), a renowned master of castle construction. Baba Nobuharu is known as one of the Twenty-Four Generals of Takeda and was the Takeda clan’s foremost castle builder, involved in the design of numerous castles.
The Okudaira Clan’s Defection and the Role of Furumiya Castle
In 1572, Okudaira Sadayoshi, the local lord who ruled this area, received a letter from Takeda Shingen confirming the security of his territory. However, the situation changed dramatically when Takeda Shingen died of illness in 1573.
Okudaira Sadayoshi and his son Sadamasa secretly allied themselves with Tokugawa Ieyasu and decided to defect from the Takeda clan. In 1573, when the Okudaira father and son left their castle, Tsukude-Kameyama Castle, and entered Takiyama Castle (later Nagashino Castle), the Takeda army advanced there.
To maintain surveillance of Kameyama Castle and control of the Tsukude region, the Takeda forces built Sainokami Castle and Monjuyama Castle on the mountain opposite Kameyama Castle, positioning Furumiya Castle as their central base. It is said that Obata Matabei, Amari Saemon, and Okuma Bizen-no-kami were stationed as castle commanders at Furumiya Castle.
Capture and Abandonment of the Castle in 1575
In the Battle of Nagashino and Shitaragahara in May 1575 (Tensho 3), the Takeda army, led by Takeda Katsuyori, suffered a crushing defeat at the hands of the Oda-Tokugawa allied forces. Following this battle, the Tokugawa army successively captured Takeda-held castles in the Tsukude region, and Furumiya Castle also fell to the Tokugawa forces.
Afterward, Furumiya Castle was abandoned, making it a short-lived castle with an effective period of use of only a few years. However, despite this short period, it remains in excellent condition to this day as a valuable historical site that conveys the Takeda clan’s castle-building techniques.
Location and Geographical Characteristics of Furumiya Castle
Strategic Position in the Tsukude Basin
Furumiya Castle is located in the central part of the Tsukude Basin, in the mountainous region of northeastern Mikawa Province. Immediately west of the castle runs the Tsukude Road, which traverses the Tsukude Basin from north to south. Furthermore, a road branching off from the Tsukude Road extends eastward from the south side of the castle, crossing the mountains and connecting to the Ina Road, making it a strategically important transportation hub in the mountainous region.
The Tsukude Basin is a plateau basin at an altitude of approximately 500 meters, surrounded by mountains, making it a natural stronghold. Furumiya Castle utilized the entire hill called Miyayama, located in the center of this basin, with a relative height of approximately 20 meters, as its fortress.
Topography as a Natural Stronghold
The small hill on which Furumiya Castle was built was surrounded by wetlands on three sides except the west, making it a natural stronghold. These wetlands made it difficult for enemies to approach, significantly enhancing the castle’s defensive capabilities.
Because the castle was built on an entire isolated small hill situated in the middle of a plain, the entire hill was fortified. The castle’s layout, which makes maximum use of the terrain, demonstrates Baba Nobuharu’s exceptional castle-building skills.
Layout and Structure of Komiya Castle
Overall Structure and Main Parts
Komiya Castle’s structure divides a small hill highly into east and west sections with a massive moat, placing the main enclosure on the eastern side surrounded by earthen ramparts. The western side features a circular enclosure, and this developed layout showcases castle-building techniques from the late Sengoku period.
The main enclosure is the central part of the castle, surrounded by high earthen ramparts. These ramparts remain well-preserved today, conveying their original appearance. To the east of the main enclosure, several enclosures are arranged in a stepped pattern, further strengthening the defenses.
Structure of the Enclosure and Masugata
One of the greatest highlights of Komiya Castle is its meticulously designed entrance (koguchi). The main enclosure’s entrance is a masugata (square enclosure) with earthen ramparts on both sides, demonstrating ingenuity in preventing enemy intrusion.
The Masugata Koguchi (square-shaped gate) is a structure that lures the enemy into a narrow space and attacks from three sides, a sophisticated defensive technique seen in castles of the late Sengoku period. The Koguchi of Furumiya Castle is believed to have retained its original form, creating a sense of realism where one can almost hear the breath of ancient soldiers in the quiet space.
Umadashi and Defensive Facilities
Furumiya Castle also features a defensive facility called an Umadashi. The Umadashi is a small enclosure built in front of the Koguchi, serving to reinforce sorties from the castle and the defense of the Koguchi.
The remains of this Umadashi are also well-preserved, making it a valuable historical castle site for understanding the defensive philosophy of the Takeda clan’s construction. The combination of the Umadashi and the Koguchi is one of the characteristics of the Takeda style of castle construction.
Arrangement of Earthworks and Vertical Moats
The key to Furumiya Castle’s defense is the earthworks and vertical moats that surround the entire castle. Earthen ramparts surround each enclosure, centered around the main enclosure, and several meters high ramparts remain in good condition today.
Vertical moats (tatebori) are moats dug vertically along the slope, serving to prevent enemy lateral movement and limit attack routes. Multiple vertical moats can be identified at Furumiya Castle, and their organic arrangement enhances the overall defensive capabilities of the hill.
Arrangement and Function of Enclosures
Furumiya Castle features multiple enclosures centered around the main enclosure. To the east of the main enclosure are the second and third enclosures, arranged in a stepped pattern, while to the west is an enclosure with a circular barbican.
These enclosures are thought to have been positioned not only for defense but also with practical functions in mind, such as the stationing of soldiers and the separated storage of supplies. Each enclosure is by earthen ramparts, designed to function as an independent defensive unit.
Characteristics of the Takeda Style of Castle Construction
Baba Nobuharu’s Castle Construction Techniques
Baba Nobuharu, who was in charge of designing the layout of Komiya Castle, is known as the Takeda clan’s foremost builder. The castles designed by Nobuharu are a culmination of advanced techniques, balancing practical defensive functions with efficient use of space.
A key characteristic of Baba Nobuharu’s castle construction techniques is the organic placement of defensive structures such as earthworks, moats, gates, and barbicans, while making maximum use of the terrain. Komiya Castle is a prime example and an indispensable historical site for learning the Takeda style of castle construction.
Perfection as an Earthen Castle
Komiya Castle was built as an “earthen castle,” without using stone walls. While castles using stone walls appeared in the late Sengoku period, traditional earthen castles were the mainstream in the Takeda clan’s territory.
The defensive system combining earthworks and moats had the advantage of shorter construction time compared to stone walls and could be built using local manpower and materials. Komiya Castle is sometimes called the “pinnacle of earthen castles,” showcasing the pinnacle of Sengoku period castle-building technology by achieving high defensive capabilities without using stone walls.
Comparison with Takeda Clan Castles
Castles built by the Takeda clan remain not only in Kai Province but also in Shinano, Suruga, Mikawa, and other regions. Komiya Castle is particularly distinctive in that it was built as a front-line base located at the eastern edge of the Takeda clan’s sphere of influence.
Compared to other Takeda clan castles, Komiya Castle is relatively small, yet its defensive facilities are densely arranged. This is thought to be because, as a front-line base, it needed to be defended efficiently with a small number of troops.
Remains and Current State of Komiya Castle
Existing Major Remains
The remains of Komiya Castle are still well-preserved, even more than 450 years after its construction. The main remains include the following:
- Earthwork of the Main Enclosure: An earthwork several meters high surrounding the main enclosure remains almost entirely intact.
- Gate and Square Enclosure: The elaborate structure of the entrance to the main enclosure remains as it was at the time.
- Horse Enclosure: Defensive facilities in front of the gate are clearly visible.
- Moat: A large moat dividing the castle area east and west.
- Vertical Moat: Multiple vertical moats dug along the slope.
- Individual Enclosures: The arrangement of multiple enclosures around the main enclosure is clearly visible.
These remains have been maintained through tree felling and undergrowth clearing, making them easily accessible for visitors.
Protection as a Shinshiro City Designated Historic Site
The Furumiya Castle Ruins are protected as a Shinshiro City Designated Historic Site. The designation date was August 10, 1971, and preservation and management by the city have been carried out ever since.
Designated as a historical site, the destruction and alteration of the remains are restricted, and it is protected as a valuable cultural asset that conveys the appearance of the Sengoku period (Warring States period). Shinshiro City regularly conducts maintenance and surveys of the remains, striving for appropriate preservation and management.
Selection as one of the Continued Top 100 Japanese Castles
On April 6, 2017 (Heisei 29), Furumiya Castle was selected as the 150th castle on the Continued Top 100 Japanese Castles list. The Continued Top 100 Japanese Castles is a list of important castles selected by the Japan Castle Association, second only to the Top 100 Japanese Castles.
This selection has led to nationwide recognition of Furumiya Castle’s historical and cultural value, attracting attention from castle enthusiasts and history lovers. The stamp for the Continued Top 100 Japanese Castles can be obtained at the Tsukude Historical and Folk Museum.
Highlights of Furumiya Castle
Earthworks surrounding the main enclosure
When visiting Furumiya Castle, first pay attention to the height and scale of the earthworks surrounding the main enclosure. The earthen ramparts of the main enclosure are about 3-4 meters high and remain uncommonly well-preserved almost all the way around.
It’s possible to walk along the top of the ramparts, offering panoramic views of the main enclosure and surrounding baileys. The structure and arrangement of the ramparts allow for an understanding of the castle’s design philosophy from the defender’s perspective.
The Elaborate Structure of the Enclosure
The entrance to the main enclosure, the gatehouse, is the highlight of Furumiya Castle. The structure of the masugata gatehouse, with earthen ramparts on both sides, is believed to have remained in its original form, making it a valuable historical site where one can directly experience the castle-building techniques of the Sengoku period.
Walking through the narrow passage of the gatehouse, one can truly appreciate the dangers faced by enemy soldiers passing through. The structure, vulnerable to attacks from the ramparts on both sides, is truly worthy of being called a “killing chamber.”
The Barbican and Defensive Line
The barbican located in front of the gatehouse is also a must-see. The barbican is a small, bailey-like structure that defended against attacks on the gatehouse and served as a base for sorties from the castle. The defensive line combining a barbican and a gate is a characteristic element of Takeda-style castle construction, and this structure can be clearly observed at Furumiya Castle. Pay attention to the arrangement of the earthworks and moats surrounding the barbican.
Arrangement of Vertical Moats
Multiple vertical moats are dug into the castle’s slopes. Vertical moats are dug perpendicularly along the slope, serving to prevent lateral movement of the enemy.
The vertical moats at Furumiya Castle have been restored, making them easier to view, and their depth and length can be truly appreciated. The arrangement parallel of multiple vertical moats indicates that they are part of a carefully calculated defensive system.
Dividing the Castle Area by Moats
The large moats dividing the castle area east and west are also a highlight. Moats are dug to cut across the ridge, preventing enemy incursions and clearly defining the castle area.
The moat at Furumiya Castle is several meters deep, and its sheer size is astonishing. Looking up from the bottom of the moat to the top of the earthen rampart, you can truly appreciate the power of this defensive structure.
Access and Visiting Information
Location
Furumiya Castle ruins are located in Miyayama, Tsukude-Kiyotake, Shinshiro City, Aichi Prefecture. The Tsukude area is located in the northern part of Shinshiro City, in a plateau basin at an altitude of approximately 500 meters, blessed with a rich natural environment.
Access
Access by Car
- Approximately 30 minutes from the Shinshiro IC on the Shin-Tomei Expressway
- Approximately 50 minutes via National Route 151 from the Toyokawa IC on the Tomei Expressway
- Parking: Parking is available at Shiratori Shrine (free of charge)
Access by Public Transportation
- Approximately 30 minutes by bus or taxi from Hon-Nagashino Station on the JR Iida Line
- Access by public transportation is not convenient; visiting by car is recommended.
Entrance and Tour Route
The entrance to Furumiya Castle starts at Shiratori Shrine at the southern foot of the mountain. A path leading to the castle ruins is maintained from the grounds of Shiratori Shrine, and guide signs are installed.
The path is relatively gentle, and it takes about 5-10 minutes on foot to reach the main enclosure. A tour route is maintained within the ruins, allowing you to visit the main remains. Please allow 30 minutes to 1 hour for the tour.
Visitor’s Notes
- Attire: Comfortable walking shoes and clothing are recommended. Be especially careful after rain, as the ground can be slippery.
- Season: Remember to bring insect repellent in summer and warm clothing in winter.
- Time: Please allow ample time to descend before sunset.
- Manners: To protect the historical site, please refrain from damaging the remains or leaving any litter.
Continued Top 100 Japanese Castles Stamp
The stamp for the Continued Top 100 Japanese Castles is located at the Tsukude Historical and Folk Museum. The museum also features exhibits and materials related to Furumiya Castle, and visiting before your visit will deepen your understanding.
Tsukude Historical and Folk Museum
- Opening Hours: 9:00 AM – 5:00 PM
- Closed: Mondays (or the following day if Monday is a public holiday), New Year holidays
-Admission Fee: Free
- Address: 35 Nawatekami, Takasato, Tsukude, Shinshiro City
Nearby Attractions
Kameyama Castle Ruins
Located approximately 2 kilometers from Komiya Castle, Kameyama Castle was the residence of the Okudaira clan. It has a close relationship with Komiya Castle, and visiting both together will provide a deeper understanding of the Sengoku period history of this region.
Nagashino Castle Ruins
Nagashino Castle Ruins, the site of the Battle of Nagashino in 1575, are also located in Shinshiro City. Selected as one of Japan’s Top 100 Castles, the Nagashino Castle Ruins Historical Preservation Museum offers detailed exhibits.
Shitaragahara Historical Museum
This museum exhibits materials related to the Battle of Nagashino and Shitaragahara. Demonstrations of matchlock guns are also held, allowing visitors to learn about battles of the Sengoku period.
Cultural Value of Komiya Castle
Research Materials on Takeda Clan Castle Construction Techniques
Komiya Castle is an extremely important historical site for studying the castle construction techniques of the Takeda clan. As an earthen without castle stone walls, its defensive structures such as earthworks, moats, and gates remain in excellent condition, making it a valuable resource for concretely understanding Sengoku period castle construction techniques.
For castle researchers and archaeologists, Komiya Castle holds high academic value as a typical example of the characteristics of Takeda-style castle construction. In particular, it is attracting national attention as a site that demonstrates the characteristics of Baba Nobuharu’s castle layout design.
Heritage that Conveys Local History
Komiya Castle is an important cultural heritage site that conveys the history of the Sengoku period in the Tsukude region. As a site that specifically shows the role that this region played during the Sengoku period, such as the conflict between Takeda Shingen and Tokugawa Ieyasu and the activities of the Okudaira clan, it contributes to local history education and tourism promotion. In Shinshiro City, Furumiya Castle is designated as an important cultural property of the region, and efforts are being made to preserve, manage, and utilize it. Regular maintenance and the installation of information boards are being implemented to create an environment where visitors can easily understand the remains.
A Preservation Model for Earthen Castles
Compared to castles with stone walls, earthen castles face the challenge of being easily lost due to weathering and erosion. Thanks to proper preservation and management, Furumiya Castle remains in good condition even more than 450 years after its construction, making it an important model for the preservation of earthen castles.
Efforts to protect the remains while improving the viewing environment, such as tree management, drainage measures, and the development of viewing paths, are examples that can serve as a reference for the preservation and management of other earthen castles.
Summary
Furumiya Castle is a flatland castle from the Sengoku period, built by Takeda Shingen as a base for his invasion of Mikawa, with the layout designed by the renowned general Baba Nobuharu. Although it wa s only in use for a short period of a few years, its elaborate layout, hailed as the “pinnacle of earthen castles,” and the excellent state of preservation of its remains have earned it high cultural value, including its selection as one of the Continued Top 100 Japanese Castles.
The remains clearly show the characteristics of Takeda-style castle construction, such as the earthen ramparts surrounding the main enclosure, the elaborate masugata koguchi (square-shaped gate), umadashi (horse enclosure), and vertical moats, making it a valuable historical site where you can experience the castle construction techniques of the Sengoku period. When visiting the Tsukude area of Shinshiro City, Aichi Prefecture, be sure to visit the ruins of Furumiya Castle and experience the castle construction techniques of the Takeda clan from 450 years ago.
The path to the castle, starting from Shiratori Shrine, is well-maintained and relatively easy to access. The stamp for the Continued Top 100 Japanese Castles can be obtained at the Tsukude Historical and Folk Museum, which also features detailed exhibits about Furumiya Castle. For anyone interested in the history and castle construction techniques of the Sengoku period, Furumiya Castle is a must-see historical site.