A Thorough Explanation of the History and Structure of Futagamiyama Castle | A Comparison of Three Castles in Inaba, Yamato, and Etchu
The name Futagamiyama Castle is recorded in Japanese history as the name of several mountain castles that existed in different regions. Castles with the same name were built mainly in Inaba Province (present-day Tottori Prefecture), Yamato Province (present-day Nara Prefecture), and Etchu Province (present-day Toyama Prefecture), each playing an important role as a regional military base. This article provides a detailed explanation of the historical background, structure, and strategic significance of these three Futagamiyama Castles.
Futagamiyama Castle in Inaba Province (Iwami District, Tottori Prefecture)
Overview and Location of Inaba Futagamiyama Castle
Futagamiyama Castle in Inaba Province was a mountain castle located in Iwazumi, Iwami-cho, Iwami-gun, Tottori Prefecture. Built on the summit of Mount Futagamiyama (338 meters above sea level), this castle functioned as the shugo (provincial governor) residence of Inaba Province from the Nanboku-cho period to the mid-Muromachi period. It is now a Tottori Prefecture designated historical site, and remnants of the original structure remain. Mount Futagami is located in the central part of Inaba Province, and its proximity to the Sea of Japan made it an ideal location for monitoring maritime traffic and as a defensive base against inland areas. From the summit, a wide area of Inaba Province could be seen, making it a strategically important location both militarily and administratively.
History of Inaba Futagami Castle
Construction History and the Yamana Clan
Inaba Futagami Castle is said to have been built during the Bunwa era (1352-1356) of the Nanboku-cho period by Yamana Tokiuji, who became the governor of Inaba Province. The Yamana clan, as a powerful daimyo under the Muromachi Shogunate, was entrusted with the rule of several provinces, including Inaba Province.
The following four points are considered to be the reasons why the Yamana clan chose Mount Futagami as their governor’s residence:
- Geographical Centrality: Located in the central part of Inaba Province, it facilitated easy governance of the entire region.
- Defensiveness: The natural fortress of the mountaintop, at an altitude of 338 meters, was well-suited for defense.
- Transportational Hub: It provided a secure communication route with Tajima Province (present-day northern Hyogo Prefecture).
- Visibility: The mountaintop offered a wide-ranging view, allowing for early detection of enemy movements.
Function as a Provincial Governor’s Office
Futagamiyama Castle was not merely a military base, but also functioned as the administrative center of Inaba Province, the provincial governor’s office. The office housed the governor’s residence, the residences of his retainers, and facilities for conducting government affairs, including public order, collecting taxes, and handling lawsuits.
To establish their control over Inaba Province, the Yamana clan used Futagamiyama Castle as a base, strategically placing branch castles and forts around it to organize their territorial control. Retainers such as Mikami Hyogo-no-kami were stationed as guards to defend the castle and maintain order.
Relocation to Fuse Tenjin-yama Castle
In Bunsho 1 (1466), the shugo (provincial governor) Yamana Katsutoyo moved his base from Futagami-yama Castle to Fuse Tenjin-yama Castle (present-day Fuse, Tottori City). Several reasons can be considered for this relocation.
- Inconvenient Location: Because Futagamiyama Castle was located on a mountaintop, it was inconvenient for daily administrative affairs and the transportation of supplies.
- Deterioration of Public Order: During the turbulent period before and after the Ōnin War, a more defensible and convenient location was needed.
- Distance from Tajima: It was located somewhat far from Tajima Province, the base of the Yamana clan, and communication took time.
- Economic Factors: It was judged that relocating to a region with more economic activity would be advantageous for governance.
Even after the relocation, Futagamiyama Castle was not completely abandoned; it is believed to have maintained its function as a subsidiary castle or watchtower for a certain period.
Structure and Remains of Inaba Futagamiyama Castle
Layout and arrangement of enclosures
Inaba Futagamiyama Castle is a typical mountain castle with multiple enclosures arranged around the mountaintop. The main enclosure was located at the highest point of the mountaintop, and the second and third enclosures were connected along the ridge, creating a linear enclosure structure.
Each enclosure was demarcated by earthen ramparts and stone walls, enhancing its defensive capabilities. The main enclosure is believed to have housed the governor’s residence and other important buildings, while the lower enclosures likely contained the residences of retainers, barracks, and warehouses.
Defense with Moats and Vertical Ditches
A defensive feature of Futagamiyama Castle is the moat cutting across the ridge and the vertical ditch descending the slope. The moat was a defensive structure dug deep into the ridge to prevent enemy intrusion, making it difficult to approach the castle.
The vertical ditch was a trench dug vertically along the mountain slope, hindering enemy lateral movement and limiting attack routes. These remains can still be seen today, demonstrating the advanced castle-building techniques of the time.
Coordination with Surrounding Forts
Futagamiyama Castle did not function in isolation, but rather formed a defensive network in conjunction with several surrounding forts. Numerous subsidiary castles, including Michitake Castle, were strategically located in the surrounding area. Information was shared through signal fires and messengers, and a system of mutual support was in place.
These forts were arranged in concentric circles around Nijōzan Castle, creating a tiered defensive line. In the event of an invasion enemy, the strategy was to first resist at the outer forts, buying time and delaying the attack on the main castle.
Nijōzan Castle in Yamato Province (Katsuragi City, Nara Prefecture)
Overview of Nijōzan Castle in Yamato Province
Nijōzan Castle in Yamato Province was a mountain castle located in the vicinity of Kamori and Someno in Katsuragi City, Nara Prefecture, and Yamada, Taishi Town, Minamikawachi District, Osaka Prefecture. Mount Nijō is a twin-peaked mountain consisting of a male peak (517 meters above sea level) and a female peak (474 meters above sea level). Nijōzan Castle was built on the northern peak, the male peak.
Historical Background of Yamato Futagamiyama Castle
A Sacred Site Since Ancient Times
Mount Futagamiyama has been an object of worship since ancient times, and was a historically important place, with the tomb of Prince Otsu located near the summit of the female peak. Even before the construction of the mountain castle, this area was recognized as an important location in Yamato Province.
A Base During the Sengoku Period
In 1499 (Meiō 8), Akazawa Tomotsune, a retainer of Hosokawa Masamoto, seized control of Yamato Province from Futagamiyama Castle. Akazawa Tomotsune, acting on orders from Hosokawa Masamoto, advanced his control of Yamato Province and utilized Futagamiyama Castle as a military and political base.
From the summit, a large part of the Yamato Basin could be seen, allowing for monitoring enemy movements and rapid response. Furthermore, its location on the border with Kawachi Province (southern Osaka Prefecture) made it suitable for monitoring the transportation routes connecting the two provinces.
The Decline of the Akazawa Clan
In 1507, when Hosokawa Masamoto was assassinated during the Eisho Rebellion, the Akazawa clan’s power rapidly declined. Having lost Masamoto’s backing, Akazawa Tomotsune was unable to maintain his control in Yamato Province, and Futagamiyama Castle gradually lost its importance.
Structure of Yamato Futagamiyama Castle
Arrangement of the Enclosures on the Summit
The summit of Mt. Otake consists of a long, two-tiered enclosure, approximately 170 meters east-west, with a higher elevation to the west and a lower elevation to the east. This vast space is called “Ninomaru,” and the tomb of Prince Otsu is also located here.
The main enclosure was situated on a higher position on the west side, with the enclosures arranged in tiers towards the east. This arrangement allowed for gradual defense against attacks from the east.
Defense Utilizing Natural Terrain
Mt. Futagamiyama has a steep mountainous terrain, making it a location with very high natural defensive capabilities. Even with minimal artificial defensive structures, the terrain itself formed a strong fortress.
The limited number of climbing routes to the summit allowed for the castle to be defended with a small force by monitoring and protecting these routes.
Futagamiyama Castle in Etchu Province (Takaoka City, Toyama Prefecture)
Overview and Location of Futagamiyama Castle in Etchu Province
Futagamiyama Castle in Etchu Province is the site of a fort built on the summit of Mount Futagami (274 meters above sea level) in Takaoka City, Toyama Prefecture. Located east of Shiroyama, where Moriyama Castle is situated, the Hiyoshi Shrine now stands on the summit, and a walking trail has been developed.
Mount Futagami is a symbolic landmark of Takaoka City, a familiar mountain visible from the city center. It has long been an object of worship and a center of mountain worship.
History of Etchu Futagamiyama Castle
While much remains unknown about the construction period and builder of Etchu Futagamiyama Castle, it is believed to have been used as a military base by a force that ruled Etchu Province during the Sengoku period.
It had a particularly close relationship with Moriyama Castle, and the two castles cooperated to form a defensive network. Futagamiyama Castle functioned as a subsidiary castle protecting the eastern side of Moriyama Castle, and they complemented each other.
Structural Features of Etchu Futagamiyama Castle
Layout Emphasizing Cooperation with Moriyama Castle
The most distinctive feature of Futagamiyama Castle is its layout, which strongly emphasizes cooperation with Moriyama Castle. Clear defensive structures such as moats and earthworks are provided in the north, east, and south directions, but no clear moats are provided to the west where Moriyama Castle is located; instead, a passage is established.
This structure facilitated the movement of allies from the west, enabling the rapid concentration of forces from both castles. Flexible operations were envisioned, such as sending reinforcements from Moriyama Castle in emergencies, or supporting Moriyama Castle from Futagamiyama Castle.
Limited Defensive Facilities
Futagamiyama Castle was more of a fort than a large-scale mountain castle. The size of the baileys was relatively small, and it is presumed that the number of troops stationed there was limited.
Its main role was lookout and information transmission; its primary task was likely to detect enemy movements early and relay that information to Moriyama Castle.
Comparison of the Three Futagamiyama Castles
Differences in Construction Purpose
Futagamiyama Castle in Inaba Province was a full-fledged mountain castle with administrative functions as a shugo (provincial governor’s office), playing a crucial role in both military and political affairs. Futagamiyama Castle in Yamato Province served as a military base for a Sengoku daimyo (feudal lord), becoming the core of regional control.
Comparison of Scale and Structure
In terms of scale, Futagamiyama Castle in Inaba Province was the largest and most complex in structure, equipped with facilities to fulfill its function as a shugo. The Futagamiyama Castle in Yamato Province is characterized by its layout, which makes full use of the vast space on the mountaintop, and possesses a defensive system that maximizes the use of the natural terrain. The Futagamiyama Castle in Etchu Province is the smallest and has a specifically designed structure for practical defense.
Location and Strategic Significance
All Futagamiyama Castles were built at respective strategically important locations in their regions. In Inaba Province, it served as a center of governance; in Yamato Province, it was a watchtower overlooking the Yamato Basin; and in Etchu Province, it was a subsidiary castle complementing the main castle, each strategically utilizing its geographical conditions to the fullest.
Remains and Current Status of Futagamiyama Castle
Current Status of Inaba Futagamiyama Castle
The Inaba Futagamiyama Castle ruins are protected as a Tottori Prefecture designated historical site, and the remains such as moats, vertical trenches, and baileys are well-preserved. A local preservation society regularly mows the grass and installs information boards, carefully preserving it as a historical heritage site.
A hiking trail is maintained, making it accessible to history enthusiasts and castle fans. The view from the mountaintop is magnificent, allowing you to experience the same scenery that the former governors must have seen overlooking Inaba Province from this location.
Current Status of Yamato Futagamiyama Castle
The ruins of Yamato Futagamiyama Castle are located on the summit of the male peak of Mount Futagami, and are popular with many hikers. As for the castle remains, only the flat areas of the baileys can be seen, and there are few clear traces of defensive structures.
Because the tomb of Prince Otsu is located here, it is also known as a sacred site of ancient history and is a popular destination for historical walks.
Current Status of Etchu Futagamiyama Castle
The ruins of Etchu Futagamiyama Castle remain around the Hiyoshi Shrine on the mountaintop. A walking trail has been developed, making it a place of relaxation for citizens. Mount Futagami, a symbol of Takaoka City, is beloved by the local community.
You can see traces of moats and baileys, and by actually seeing the positional relationship with Moriyama Castle, you can understand the defense system of the time.
Medieval Military Strategy as Told by Futagamiyama Castle
The Role and Function of Mountain Castles
The three castles bearing the name Futagamiyama Castle each demonstrate the diverse roles that mountain castles played in different eras and regions. The three types—administrative functions as a shugo (provincial governor’s) residence, military bases of Sengoku daimyo (warring states lords), and subsidiary castles complementing the main castle—symbolize the development and diversification of mountain castles in medieval Japan.
Castle Construction Techniques Utilizing the Topography
All Futagamiyama Castles were built making maximum use of the mountainous terrain of “Futagamiyama” in that area. Effective defensive systems were constructed, such as the arrangement of baileys, the installation of moats, and the construction of vertical trenches, according to the elevation and topographical characteristics.
These castle construction techniques are the culmination of ingenuity in achieving maximum defensive effectiveness with limited resources and labor, demonstrating the high level of military engineering in the medieval period.
Transportation and Information Networks
Mountain castles did not function in isolation, but rather formed networks in cooperation with surrounding castles and fortresses. A well-organized defense system was in place, including information dissemination via beacon fires and messengers, and the establishment of mutual support systems.
The example of Futagamiyama Castle is a valuable document demonstrating how medieval lords strategically positioned their castles and established efficient systems of control.
Summary
The name Futagamiyama Castle exists in three locations: Inaba Province, Yamato Province, and Etchu Province, each possessing its own unique historical background and structural characteristics. The Futagamiyama Castle in Inaba Province served as a shugo (provincial governor) residence from the Nanboku-cho period to the Muromachi period; the Futagamiyama Castle in Yamato Province served as a military base during the Sengoku period; and the Futagamiyama Castle in Etchu Province played a crucial role as a subsidiary castle complementing the main castle.
These castles still retain remains today, conveying the castle-building techniques and military strategies of the time. The example of Futagamiyama Castle clearly demonstrates how the uniquely Japanese mountain style skillfully utilized the terrain to construct an effective defensive system.
For history enthusiasts, visiting these three Futagamiyama castles and comparing their unique features will be a valuable experience for understanding the military and regional history of medieval Japan. By superimposing the landscapes seen by past warlords onto the views from the mountaintops, history becomes more relatable and vibrant.
