Ametaki Castle (Kagawa Prefecture) Complete Guide | Thorough Explanation of History, Remains, and Access
Basic Information on Ametaki Castle
Ametaki Castle is a medieval mountain castle located in Tomitanaka, Okawa-cho, Sanuki City, Kagawa Prefecture. Built on the summit of Mt. Ametaki (253.2m above sea level) and the ridges extending in three directions from it, it played an important role as the base of the Yasutomi clan, who ruled the eastern Sanuki region.
Location and Basic Data
- Location: Tomita-naka, Okawa-cho, Sanuki City, Kagawa Prefecture
- Former Province: Sanuki Province
- Elevation: 253.2m
- Relative Height: Approximately 230m (Approximately 60m from the castle entrance)
- Classification and Structure: Mountain Castle
- Builder: Yasutomi Morinaga
- Year of Construction: Chōroku era (1457-1460)
- Main Lords: Yasutomi clan, Rokusha clan
- Year of Abandonment: Tenshō 11 (1583)
- Remains: Enclosures, moats, earthworks, stone walls
- Keep Structure: None (As it is a medieval mountain castle, there is no keep)
History of Amataki Castle
The Yasutomi Clan’s Entry into Sanuki Province and Castle Construction
The Yasutomi clan was a samurai family that ruled Mikazuki-go in Harima Province (present-day Hyogo Prefecture). There are two theories regarding their origins: one that they were of the Ki clan, and another that they were of the Tada Minamoto clan. It is also said that they had roots in Shimosa Province. Around the Oan era (1368-1375), they entered Sanuki Province following Hosokawa Yoriyuki.
During the Chōroku era (1457-1460), Yasutomi Morinaga built a castle on Amatakiyama and moved it to his base. During this period, the system of governance in Sanuki Province was being established under the influence of the Hosokawa clan, and the Yasutomi clan came to occupy an important position as the deputy governor of eastern Sanuki.
Yasutomi Morinaga as one of the Four Heavenly Kings of Hosokawa
During the Ōnin War (1467-1477), Yasutomi Morinaga played an active role as a powerful retainer of the Hosokawa clan, becoming a warrior who was counted as one of the “Four Heavenly Kings of Hosokawa.” During this period, the Yasutomi clan was the most powerful local lord in eastern Sanuki, wielding significant influence over the surrounding region.
Amataki Castle served not merely as a residence, but also as a base for controlling eastern Sanuki and a crucial military stronghold supporting the Hosokawa clan’s rule over Sanuki.
Relationship with the Miyoshi Clan and the Turmoil in Eastern Sanuki
As the Sengoku period began, the power dynamics within Sanuki became increasingly complex. In 1572, Yasutomi Moritada (a descendant of Yasutomi Morinaga) married the daughter of Shinohara Danjo Nyudo Shion, a vassal of Miyoshi Nagaharu, and formed an alliance with the Miyoshi clan.
Based on this alliance, the Miyoshi clan attacked the Kangawa clan, a powerful local lord in eastern Sanuki. The Kangawa clan was forced to retreat from Toramaru Castle to Hirune Castle, significantly altering the balance of power in eastern Sanuki. It is believed that Amataki Castle functioned as a crucial base during the Miyoshi clan’s invasion of eastern Sanuki during this period.
The Invasion and Fall of the Castle by Chosokabe Motochika
During the Tensho era, Chosokabe Motochika of Tosa Province began an aggressive invasion aimed at unifying Shikoku. In 1583 (Tensho 11), the Chosokabe army launched a full-scale invasion of Sanuki Province, and Amataki Castle became one of its targets.
Chosokabe Motochika established encampments around Amataki Castle and waged a well-organized siege. After a long siege, Amataki Castle finally fell, marking the end of the Yasutomi clan’s rule over eastern Sanuki. This led to the decline of the Yasutomi clan’s power, which had ruled eastern Sanuki for approximately 130 years.
After its fall, Amataki Castle was abandoned and never rebuilt.
Layout and Remains of Amataki Castle
Characteristics of the Castle Structure
Amataki Castle is a typical medieval mountain castle with baileys arranged on ridges extending in three directions, centered around the summit of Mt. Amataki (elevation 253.2m). It is characterized by a centripetal layout centered on the main bailey and defensive lines utilizing the ridges.
Currently, hiking trails are maintained, making the area around the main bailey relatively easy to visit. However, many parts of the ridges outside the main bailey are overgrown with vegetation, requiring caution when examining the remains.
Main Bailey (Honmaru)
The main bailey, located at the summit, is the core of the castle. From here, one can overlook a wide area of eastern Sanuki, and it functioned as a military and political base. Traces of earthworks can be seen around the main bailey, indicating the presence of defensive structures.
Group of Baileys
Multiple baileys are arranged on the ridges extending in three directions from the main bailey. These enclosures were arranged in stages, forming a multi-layered defensive system to prevent enemy incursions. The size and shape of each enclosure varied according to the terrain, demonstrating the unique use of topography characteristic of medieval mountain castles.
Moats
Moats, which cut off the ridgelines, were an important defensive feature of Amataki Castle. Multiple moats have been identified, with particularly clear ones remaining on the ridges that served as major access routes. These moats played a crucial role in preventing enemy advances and enhancing the castle’s defensive capabilities.
Earthworks
Earthworks were constructed around the perimeters of the enclosures and at key points, some of which are still clearly visible today. These earthworks served not only as defensive walls but also to clearly define the boundaries of the enclosures.
Stone Masonry
Traces of stone masonry have been found in some areas of Amataki Castle. While the use of stone masonry in medieval mountain castles was generally limited, it is evident that stone reinforcement was used in important locations.
Ascent Route and Access Information
Entrance and Parking
The ascent to Amataki Castle begins at the trailhead located at the foot of the mountain. There is parking space near the trailhead, making it accessible by car. However, parking is limited, so caution is advised, especially on weekends and during hiking season.
Ascent Route
The elevation difference from the trailhead to the main enclosure is approximately 60m, and the climb is relatively easy using the well-maintained hiking trail. The estimated time is approximately 20-30 minutes one way.
However, if exploring the ridge areas outside the main enclosure, long sleeves and long pants are recommended due to the many overgrown areas. Also, since there are slippery sections, appropriate footwear such as trekking shoes is recommended.
Access Methods
Access by Car
- Approximately 15 minutes from Tsuda-Samukawa IC on the Takamatsu Expressway
- Approximately 40 minutes from central Takamatsu City via National Route 11
Access by Public Transportation
- Approximately 15 minutes by taxi from Sanuki-Tsuda Station on the JR Kotoku Line
- Bus services are limited, so access by car is recommended.
Precautions When Visiting
- Check the weather before climbing the castle. Be careful as the ground can be slippery in rainy or rainy weather.
- Carrying insect repellent is recommended during the summer.
- Always bring drinking water.
- Mobile phone reception may be unstable in some areas.
- To protect the remains, please refrain from climbing on earthworks and stone walls.
Related Castles in the Surrounding Area
Toramaru Castle
Toramaru Castle, the base of the Samukawa clan, is located northwest of Amataki Castle. In 1572 (Genki 3), the Kagawa clan retreated from Toramaru Castle due to an attack by the Miyoshi clan and moved to Hirune Castle. This event demonstrates the significant impact the alliance between the Yasutomi and Miyoshi clans had on the power dynamics of eastern Sanuki.
Hirune Castle
This castle served as a base for the Kagawa clan after their retreat from Toramaru Castle. The relationship between Amataki Castle and Hirune Castle is important for understanding the power struggles in eastern Sanuki during the Sengoku period.
Chausuyama Castle
This castle is believed to have been the base of operations for Chosokabe Motochika when he attacked Amataki Castle. Located south of Amataki Castle, it is an important historical site for understanding the Chosokabe army’s siege strategy. The distance and relative position of Chausuyama Castle to Amataki Castle provide clues to understanding military tactics at the time.
Connection to Amataki Natural Science Museum
At the foot of Amataki Castle is the “Amataki Natural Science Museum,” which features exhibits on the nature and history of the region. When visiting Amataki Castle, stopping by this science museum will allow you to gain a deeper understanding of the region’s historical background and natural environment.
Historical Significance of Amataki Castle
As a Base for Controlling Eastern Sanuki
Amataki Castle functioned as the political and military center of the Eastern Sanuki region from the Muromachi period to the Sengoku period. It was an indispensable base for the Yasutomi clan as the Hosokawa clan’s deputy governor, governing the region.
An Example illustrating the Trends of the Sanuki Local Lords
The rise and fall of the Yasutomi clan is a typical example illustrating the trends of the local lords in medieval Sanuki. The Yasutomi clan, who entered Sanuki under the Hosokawa clan and expanded their power as deputy governors, allied themselves with the Miyoshi clan amidst the chaos of the Sengoku period, and ultimately declined due to the invasion of the Chosokabe clan. This process illustrates the shifts in regional power during the Sengoku period.
Its Place in the Process of Unifying Shikoku
In the process of Chosokabe Motochika’s unification of Shikoku, the capture of Amataki Castle was a crucial stage in the invasion of Sanuki. The fall of this castle allowed the Chosokabe clan to establish their influence in eastern Sanuki and advance towards controlling the entire region.
The Charm and Highlights of Amataki Castle
Well-Preserved Medieval Mountain Castle Remains
The greatest charm of Amataki Castle is the relatively well-preserved layout and remains of this medieval mountain castle. Basic defensive structures such as moats, baileys, and earthworks can be seen firsthand, allowing visitors to experience the structure of a medieval castle.
Stunning Views
From the main bailey at the summit, you can enjoy a panoramic view of the vast landscape of eastern Sanuki. On clear days, you can see the Seto Inland Sea and the surrounding mountains, giving you a real sense of the strategic importance of this location.
Enjoyment as a Hiking Spot
Well-maintained hiking trails allow you to enjoy both castle exploration and nature walks simultaneously. The moderate exercise makes it popular not only with castle enthusiasts but also with general hiking lovers.
Current Status and Challenges of Amataki Castle Research
Status of Archaeological Excavations
At Amataki Castle, full-scale archaeological excavations have been limited, and research has primarily relied on historical documents and on-site surveys. Further detailed surveys and partial excavations could potentially provide more information about the castle’s structure and history.
Deepening Research on the Yasutomi Clan
While the basic genealogy and achievements of the Yasutomi clan are clear, there is room for further research into their detailed activities and relationships with other local lords of Sanuki Province. In particular, research into their migration process from Harima to Sanuki and their specific power structure in eastern Sanuki is anticipated.
Summary
Amataki Castle is a medieval mountain castle built on Mount Amataki in Sanuki City, Kagawa Prefecture. It played an important role for approximately 130 years as the base of the Yasutomi clan, who ruled eastern Sanuki. Built by Yasutomi Morinaga during the Chōroku era (1457-1460), Amataki Castle held a significant position in the political and military history of Sanuki Province until its fall in 1583 to Chōsokabe Motochika’s invasion.
Even today, the remains of the castle, including baileys, moats, and earthworks, are well-preserved on the 253.2m-high mountaintop, making it a valuable historical site for learning about the structure of medieval mountain castles. It is relatively easy to access via well-maintained hiking trails, making it a recommended spot not only for castle enthusiasts but also for history buffs and nature lovers.
Visiting Amataki Castle allows for multifaceted historical learning, including the rise and fall of regional powers in Sanuki Province during the Sengoku period, the defensive systems of medieval mountain castles, and the military strategies of the Chōsokabe clan aiming for the unification of Shikoku. When visiting Kagawa Prefecture, be sure to visit this historic mountain castle.
