Complete Guide to Tadotsu Castle (Kagawa Prefecture) | History, Remains, and Access to the Kagawa Clan’s Residence and Motodaiyama Castle
What is Tadotsu Castle?
Tadotsu Castle (Tadotsu-jo) is a medieval mountain castle located in Momoyama, Tadotsu-cho, Nakatado-gun, Kagawa Prefecture. Also known as Motodaiyama Castle, it was built on the eastern edge of a mountain approximately 93 meters above sea level, overlooking Tadotsu Port. Currently, it is maintained as Toryo Park and serves as a place of relaxation for local residents.
The Kagawa clan, who ruled the western part of Sanuki Province (present-day Kagawa Prefecture), used it as their residence during peacetime, and it played an important role as part of a castle system, with the rear castle, Amagiri Castle, functioning as a fortified outpost during wartime.
Basic Information on Tadotsu Castle
Location and Map
- Location: Momoyama (Higashishinmachi), Tadotsu-cho, Nakatado-gun, Kagawa Prefecture
- Former Province: Sanuki Province
- Alternate Name: Hondaiyama Castle
- Current Status: Tōryō Park
- Elevation: Approximately 93 meters
- Relative Height: Approximately 80 meters
Tadotsu Castle is located about a 20-minute walk west from Tadotsu Station, the junction of the JR Yosan Line and Dosan Line, and is situated at a transportation hub facing the Seto Inland Sea.
Castle Classification and Structure
- Classification: Mountain Castle
- Construction Style: Medieval Mountain Castle
- Layout: Details unknown (due to few remaining structures)
- Keep Structure: None (as it is a medieval castle, there is no keep)
- Main Remains: Part of the stone wall, remains of baileys, flat area resembling a belt bailey
Builder and Lord
- Builder: Kagawa Hyobu-shoyu Kagefusa
- Year of Construction: Joji era (1362-1368) or Shohei era (1346-1370)
- Main Lords: Successive generations of the Kagawa clan
- Year of Abandonment: Estimated Tensho era (1573-1593)
History of Tadotsu Castle
The Kagawa Clan’s Entry into Sanuki Province and the Construction of Tadotsu Castle
The history of Tadotsu Castle dates back to the Nanboku-cho period (Northern and Southern Courts period). It is said to have been built during the Jōji era (1362-1368) by Kagawa Hyōbu-no-shōyū Kagefusa, who moved to Sanuki Province with Hosokawa Yoriyuki, the governor of Sanuki.
The Kagawa clan are said to be descendants of Kamakura Kagemasa. Originally samurai from the Kanto region, they entered Sanuki Province as subordinates of the Hosokawa clan and expanded their power as deputy governors of the western Sanuki region. Tadotsu Castle played an important role as one of their bases.
Function as a Peacetime Residence
The Kagawa clan used Tadotsu Castle as their peacetime residence. This means it functioned as a base for daily administrative affairs and territorial management. On the other hand, during wartime or emergencies, they employed a two-castle system, using Amagiri Castle, built on the rear of Mount Amagiri (approximately 270 meters above sea level), as a secondary fort.
This castle layout is a typical example of medieval castle design, where the residence was located in a convenient, relatively flat area, and the fortress was situated in a mountainous stronghold in times of emergency. Tadotsu Castle offered a panoramic view of the Seto Inland Sea and Tadotsu Port, making it an ideal location for monitoring maritime traffic and managing the port.
The Kagawa Clan’s Expansion
From the Nanboku-cho period to the Muromachi period, the Kagawa clan expanded their power as the deputy governor of western Sanuki Province, extending their influence not only around Tadotsu but also to the Zentsuji and Mitoyo regions. Within the Kagawa clan’s territory, in addition to Amagiri Castle, there were several branch castles, including Koyama Castle, Tarumizu Castle, and Shōtsūji Castle, with Tadotsu Castle being the central residence overseeing them all.
Tadotsu had long flourished as a key point for maritime and land transportation, functioning as an important port on the Seto Inland Sea route. It is believed that the Kagawa clan leveraged this geographical advantage to build a strong economic and military base.
The Invasion and Subjugation of the Chosokabe Clan
During the Tensho era (1573-1593), Chosokabe Motochika, a Sengoku daimyo of Tosa Province, began his invasion of Sanuki Province with the aim of unifying Shikoku. The Kagawa clan initially resisted, but ultimately submitted to the Chosokabe clan due to their overwhelming military power.
While the exact role of Tadotsu Castle during this period is unclear, it is believed that the Kagawa clan’s influence significantly diminished within the Chosokabe clan’s control of Sanuki. Later, after Toyotomi Hideyoshi’s conquest of Shikoku, the Chosokabe clan was reduced to Tosa Province alone, and Sanuki Province came under the control of the Ikoma clan. It is presumed that Tadotsu Castle was abandoned.
After the Edo Period
During the Edo period, Tadotsu became part of the Marugame Domain, and later the Tadotsu Domain was established. However, the Tadotsu Domain’s administrative office was located at the Tadotsu Jinya (fortified residence), and Tadotsu Castle was never reused.
Since the Meiji era, the castle ruins have been developed into Tōryō Park, which remains so to this day.
Remains and Highlights of Tadotsu Castle
Current Tōryō Park
The Tadotsu Castle ruins are now developed as Tōryō Park, a popular place for local residents to stroll and relax. Walking paths are maintained within the park, making it relatively easy to climb to the top of the hill.
From the park, you can enjoy a panoramic view of Tadotsu Port and the Seto Inland Sea. On clear days, you can see the Seto Ohashi Bridge and the surrounding islands. This excellent view was likely one of the reasons the Kagawa clan chose this location as their castle.
Traces of Stone Walls
Within Tōryō Park, there are a few places where traces of stone walls can be seen. The remains of relatively well-organized stonework for a medieval castle offer a glimpse into the castle’s structure at the time.
However, due to later park development and construction, many remains have been lost, making it difficult to clearly identify the castle’s layout. Nevertheless, with careful observation, you can find topographical features that appear to be the remains of baileys (kuruwa) and earthworks.
Remains of Baileys and Terraced Baileys
While water facilities are located on the mountaintop, terraced bailey-like flat areas can be observed around them. The central area is slightly elevated, and there is a place that is thought to be the main bailey (honmaru).
These terrain features likely utilize the natural landscape while being artificially leveled, giving a sense of the castle’s atmosphere to some extent. For castle enthusiasts, this is a place where you can enjoy imagining its appearance from the few remaining traces.
Estimated Layout
The detailed layout of Tadotsu Castle is unknown, but it is presumed to have been a mountain castle with a main bailey on the mountaintop and several baileys arranged on the slopes, in a concentric or tiered bailey style. Given its location facing the sea, it is highly likely that the castle structure was primarily intended for monitoring and defending the harbor.
Considering its relationship with Amagiri Castle, Tadotsu Castle is thought to have had a stronger character as a residence for daily living and territorial management, rather than as a large-scale military facility.
Relationship with Amagiri Castle
Amagiri Castle as a Fortified Outpost
When discussing Tadotsu Castle, it is essential to mention Amagiri Castle on Mount Amagiri, which rises behind it. Amagiri Castle is a mountain castle built on the summit of Mount Amagiri, approximately 270 meters above sea level, spanning Zentsuji City, Mitoyo City, and Tadotsu Town, and functioned as a fortified outpost for the Kagawa clan.
A fortified outpost is a stronghold used to take refuge in when one’s main castle is attacked. It is thought that if Tadotsu Castle were attacked, the Kagawa clan would retreat to Amagiri Castle to resist.
Strategic Significance of the Two-Castle System
The two-castle system of Tadotsu Castle and Amagiri Castle was a rational castle layout that balanced convenience and defensive capabilities. Tadotsu Castle, being close to the port, was convenient for daily administrative affairs and trade, but its defensive capabilities were limited. On the other hand, Amagiri Castle, built on a steep mountain, was a difficult fortress to conquer, but inconvenient for daily life.
By utilizing these two castles strategically, the Kagawa clan maximized both the efficiency of peacetime governance and the defensive strength during wartime. This type of castle management was widely seen among samurai groups in medieval western Japan.
Related Castles in the Surrounding Area
Marugame Castle
Located approximately 5 kilometers east of Tadotsu Castle, Marugame Castle is a modern castle built during the Edo period. It served the Ikoma and Yamazaki clans before becoming the residence of the Kyogoku clan, and is known as a famous castle with a surviving keep.
While Tadotsu Castle was a medieval mountain castle, Marugame Castle is a modern flatland castle, making it an interesting example for comparing the evolution of castle architecture over time.
Kōyama Castle, Tarumizu Castle, and Shōtsūji Castle
Within the Kagawa clan’s sphere of influence were several subsidiary castles, including Kōyama Castle, Tarumizu Castle, and Shōtsūji Castle. These formed a network of castles centered around Tadotsu Castle and Amagiri Castle, supporting the Kagawa clan’s control over the western Sanuki region.
Those who enjoy visiting castles will gain a deeper understanding of the Kagawa clan’s overall domain management by visiting these related castles as well.
Tadotsu Jinya
The Tadotsu Jinya, the administrative center of the Tadotsu Domain during the Edo period, was located separately from Tadotsu Castle. While not a castle, the Jinya was an administrative facility, but it is an important historical site for understanding the history of Tadotsu.
Access and Parking Information
Access by Public Transportation
- Walking from JR Tadotsu Station: Approximately 20 minutes
- Tadotsu Station, where the JR Yosan Line and Dosan Line diverge, is a key point for railway transportation in Shikoku.
- Head west from the station towards Tadotsu Port to reach the entrance of Momoryo Park.
Access by Car
- From Takamatsu Expressway, Zentsuji IC: Approximately 15 minutes
- From Seto-Chuo Expressway, Sakaide IC: Approximately 20 minutes
- Car Navigation Setting: Search for “Momoryo Park” or “Tadotsu-cho Momoyama”
Parking
Momoryo Park has its own parking lot, which is free to use. However, the number of parking spaces is limited, so it may be crowded on holidays and during cherry blossom season.
Points to Note When Visiting
- The park is well-maintained, but there are some steep slopes and stairs.
- We recommend wearing comfortable shoes.
- As there are few remaining structures, learning about the history beforehand will deepen your understanding.
- Don’t forget insect repellent in summer and warm clothing in winter.
How to Enjoy Visiting Tadotsu Castle
Feeling the Romance of History
Although Tadotsu Castle has few remaining structures, it holds significant historical importance as a base where the Kagawa clan controlled western Sanuki Province. From the few traces of stone walls and the undulations of the terrain, you can enjoy imagining the life and strategies of medieval samurai.
Known as a “castle of traces” among castle enthusiasts, it has a different charm than castles with clearly remaining structures. Visiting with an understanding of the historical background will provide a不思議な experience where you can see things that were previously hidden.
Enjoying the View
The view from Momoryo Park is magnificent, offering a panoramic view of Tadotsu Port, the Seto Inland Sea, and the Seto Ohashi Bridge. The scenery, especially at sunset, is beautiful and makes for a great photo spot.
It’s possible that the Kagawa clan also contemplated their domain’s management and strategies while gazing at this view. Viewing the scenery from the perspective of the castle lord at the time deepens your understanding of history.
Combining with surrounding sightseeing
Besides Tadotsu Castle, Tadotsu Town has other attractions.
- Tadotsu Port: Retains the atmosphere of an old port town.
- Cherry Blossoms at Momoryo Park: A popular cherry blossom viewing spot in spring.
- Tadotsu Fireworks Festival: A summer tradition.
- Kaiganji Temple: An ancient temple associated with Kobo Daishi.
Marugame Castle, Zentsuji Temple, and Kotohira Shrine are also within a 30-minute drive, making a visit to Tadotsu Castle a good addition to your Sanuki sightseeing.
Historical Evaluation of Tadotsu Castle
Compared to famous castles with large stone walls and keeps, Tadotsu Castle may seem unremarkable at first glance. However, it is an important historical site for understanding the realities of regional rule in medieval Sanuki Province.
The two-castle system adopted by the Kagawa clan—a peacetime residence and a secondary castle—is noteworthy from the perspective of castle research as a typical example of castle management by medieval samurai groups. Furthermore, as a castle located at a strategic point for maritime traffic, it is significant in considering the history of the Seto Inland Sea shipping routes.
While the scarcity of remaining structures is unfortunate, this also allows for the enjoyment of using one’s imagination to feel the history. For castle enthusiasts, it is a place where one can experience the quiet joy of exploration, different from that of famous castles.
Summary
Tadotsu Castle (Motodaiyama Castle) was a medieval mountain castle located in Tadotsu-cho, Nakatado-gun, Kagawa Prefecture, and played an important role as the peacetime residence of the Kagawa clan, who ruled western Sanuki Province. Currently developed as Momoryo Park, the site retains only faint traces of stone walls and baileys, evoking a sense of its former glory.
Tadotsu Castle, with its two-castle system including Amagiri Castle as its main stronghold, its location overlooking the Seto Inland Sea, and the rise and fall of the Kagawa clan, encapsulates the history of medieval Sanuki. While few remains exist, a visit with an understanding of its historical context will undoubtedly lead to profound emotions and new discoveries.
Easily accessible on foot from Tadotsu Station, the surrounding area boasts numerous tourist attractions such as Marugame Castle and Kotohira Shrine. When visiting Sanuki, be sure to stop by Tadotsu Castle ruins. A tranquil castle site awaits you, where you can feel the spirit of medieval samurai.
