Akayama Castle (Kawaguchi City, Saitama Prefecture) Complete Guide: The Base and Historical Remains of the Ina Clan, Kanto Regional Governor
What is Akayama Castle?
Akayama Castle (Akayama-jō) is an Edo period castle located in Akayama, Kawaguchi City, Saitama Prefecture. It is commonly known as “Akayama Jin’ya” and is currently protected as a Saitama Prefecture designated cultural property (historical site).
Built in 1629 (Kanei 6) during the early Edo period by Ina Tadaharu, who served as the Kanto Regional Governor, this castle differed from typical castles with keeps and stone walls. Instead, it was a jin’ya-style castle primarily composed of earthworks and moats. However, its scale was vast, covering 77 hectares, and it functioned as a major base, encompassing the main keep, second keep, vassal residences, and a family temple.
Even today, remnants of dry moats and earthworks remain throughout the castle site, making it a valuable historical heritage site that conveys the characteristics of Edo period jin’ya architecture.
History of Akayama Castle
The Ina Clan and the Kanto Regional Governor
The Ina clan is indispensable when discussing the history of Akayama Castle. The Ina clan traces its ancestry to Ina Tadatsugu, who served Tokugawa Ieyasu, and was a family that held the important position of Kanto Regional Governor for generations.
The Kanto Regional Governor was one of the important positions in the Edo Shogunate, responsible for overseeing the administration of the shogunate’s direct territories (tenryo) in the Kanto region, as well as flood control, water utilization projects, and new land development. The Ina clan inherited this position and made a significant contribution to the development of the Kanto region.
History of Castle Construction
In 1618 (Genna 4), Ina Tadatsugu’s eldest son, Tadamasa, the first Kanto Regional Governor, died, and his second son, Ina Tadaharu, inherited the family headship. At this time, Tadaharu received the Akayama territory of 7,000 koku from the shogunate. The Akayama domain comprised 25 to 28 villages, encompassing parts of present-day Kawaguchi City (northeastern part), Soka City, and Saitama City.
In 1629 (Kanei 6), Tadaharu moved his residence from Komuro (present-day Ina-machi, Kita-Adachi-gun, Saitama Prefecture) to this location in Akayama and built Akayama Castle. This location was chosen because it was strategically situated in the Kanto Plain, making it suitable for supervising flood control projects and land reclamation.
Achievements of the Ina Clan
The Ina clan, based at Akayama Castle, made significant contributions to the development of the Kanto region.
Flood Control Projects: They directed large-scale river improvement projects, including the diversion of the Tone River, mitigating flood damage in the Kanto Plain. This improved agricultural production and stabilized the lives of many people.
Land Reclamation: They reclaimed wetlands and wasteland, creating new farmland. This greatly contributed to increasing food production to meet the growing population of Edo.
Disaster Relief Activities: During times of famine and disaster, they actively engaged in relief efforts, protecting the lives of their people.
Urban Development: They were involved in the urban development of Edo, including the reclamation and urbanization of Fukagawa in Edo.
These projects were continued by successive generations of the Ina clan, from the fourth generation, Ina Tadakatsu, supporting the development of the Kanto region.
Dispossession and Abandonment of the Castle
The Ina clan’s rule over Akayama Castle, which lasted for 163 years, came to a sudden end in 1792 (Kansei 4).
The 12th head of the family, Ina Tadataka, caused a family dispute due to a succession dispute over an adopted son and his own misdeeds. The shogunate, taking this situation seriously, sentenced Tadataka to permanent house arrest and confiscated the Ina family’s territory.
As a result, Akayama Castle was abandoned, and the buildings of the encampment were dismantled. Thus, the era of the Ina clan, who had supported the development of the Kanto region for a long time, came to an end.
Structure and Scale of Akayama Castle
Vast Grounds
The most distinctive feature of Akayama Castle is its vast grounds. At 77 hectares (approximately 230,000 tsubo), it was an exceptionally large size for an Edo period encampment. This is equivalent to approximately 16 Tokyo Domes.
Within this vast grounds, various facilities were arranged, including the main keep, the second bailey, numerous vassal residences, a family temple, and stables.
Layout (Castle Arrangement)
Akayama Castle adopted the typical form of a flatland castle. The main keep was located in the center, surrounded by the second bailey, with vassal residences and related facilities extending further outwards.
For defensive structures, earthen ramparts and dry moats were used rather than stone walls. This reflects the topographical characteristics of the Kanto Plain and the peaceful historical context of the Edo period.
Earthworks and Dry Moats
The most important remaining structures of Akayama Castle are the earthworks and dry moats.
Earthworks are defensive walls built by piling up earth, and at Akayama Castle, several earthworks reaching several meters in height remain in various places. It is believed that fences or walls were built on top of the earthworks.
Dry moats are moats that do not hold water, and they surrounded the main keep and the second bailey. The dry moats that remain clearly visible today are extremely valuable resources for understanding the castle structure of the time.
Main Gate and Major Facilities
The main gate was the main entrance to the castle and could be considered the face of Akayama Castle. Currently, a stone monument and an information board have been erected where the main gate once stood, allowing us to imagine its former appearance.
The residence of the Ina clan was located in the main keep, and it was the center of government and daily life. It is believed that the Ninomaru (second enclosure) contained the residences of senior retainers and buildings that housed administrative functions.
Current State of Akayama Castle Ruins
Preservation and Development
Currently, most of the Akayama Castle ruins are covered with woodlands, nurseries, and residential areas, but a portion centered around the main enclosure (Honmaru) has been developed as a castle ruins park.
It is protected as a Saitama Prefecture designated cultural property (historical site), and walking paths have been developed, allowing visitors to observe the dry moats and earthworks up close. The restored dry moats serve as an extremely effective teaching tool for understanding the castle structure of the time.
Iina Park Kawaguchi (Akayama Historical Nature Park)
Near the Akayama Castle ruins is “Iina Park Kawaguchi” (Akayama Historical Nature Park). This park is a comprehensive park where visitors can learn about the history of Akayama Castle and enjoy nature.
At the Historical and Natural Museum within the park, you can see a detailed model of the Akayama Jinya (fortified residence) and exhibits related to the history of the Ina clan. The model is highly appreciated by visitors as it helps them visually understand the overall layout of the castle at the time.
The museum also displays materials related to flood control projects and land reclamation undertaken by the Ina clan, allowing visitors to learn about the development history of the Kanto region during the Edo period.
Main Highlights
Main Enclosure Site: The main enclosure area, where the earthworks and dry moats remain in good condition.
Second Enclosure Site: The area surrounding the main enclosure, with some remains still present.
Outer Moat Site: An explanatory sign is located near the Kawaguchi Line of the Metropolitan Expressway, allowing visitors to appreciate the former size of the castle grounds.
Main Gate Site: A stone monument and information board mark the castle entrance.
Earthworks: The earthworks remaining in various locations differ in height and shape, each possessing its own unique characteristics.
Access Information
Access by Train
Saitama Rapid Railway: Approximately 20 minutes on foot from Arai-juku Station
JR Musashino Line: Take the bus bound for Hatogaya from the South Exit of Higashi-Kawaguchi Station, get off at the “Kuruwa” bus stop, and walk for approximately 3 minutes.
JR Keihin-Tohoku Line: Take the bus bound for Kawaguchi Municipal Medical Center via Mine Hachimangu Shrine and Arai-juku Station from the East Exit of Kawaguchi Station, get off at the “Kuruwa” bus stop, and walk for approximately 3 minutes.
SR Saitama Stadium Line: Approximately 20 minutes on foot from Tozuka-Angyo Station
Access by Car
Shuto Expressway Kawaguchi Line: Approximately 5 minutes south from Kawaguchi-Higashi Interchange
Parking is available at Iina Park Kawaguchi (Akayama Historical Nature Park).
Surrounding Facilities
- Iina Park Kawaguchi (Akayama Historical Nature Park)
- Historical Nature Museum
- Mine Hachimangu Shrine
- Kawaguchi Municipal Medical Center
Cultural Value of Akayama Castle
Saitama Prefecture Designated Cultural Property
Akayama Castle ruins are officially designated as a Saitama Prefecture Designated Cultural Property (Historical Site). This is proof that it is recognized as having high historical and academic value and the need for preservation.
A Typical Example of Edo Period Jinya Architecture
Akayama Castle occupies an important position in the study of architectural history and castle history as a typical example of Edo period Jinya architecture. It conveys the appearance of a Jinya, a practical administrative office, different from the early modern castles with keeps.
A Witness to the History of Flood Control and Water Utilization
Akayama Castle, the base of the Ina clan, is indispensable when discussing the history of flood control and water utilization in the Kanto region. Numerous projects directed from here laid the foundation for the present-day Kanto Plain.
How to Enjoy Your Visit to Akayama Castle
Historical Walking Course
When visiting Akayama Castle ruins, the following course is recommended:
- Gain background knowledge at the History and Nature Museum in Iina Park Kawaguchi
- Understand the overall layout with the Akayama Jinya model
- Enter the castle ruins from the Otemon Gate ruins
- Observe the earthworks and dry moat of the main keep ruins
- Explore the second bailey ruins
- Check the explanatory sign for the outer moat ruins
- Observe the various remains while walking along the promenade
The estimated time required, including the museum visit, is approximately 2-3 hours.
Photo Spots
The earthworks and dry moat of the castle ruins show different expressions in each of the four seasons. Especially during the seasons of fresh greenery and autumn leaves, you can take photos that harmonize the beauty of historical remains and nature.
Learning Points
When visiting Akayama Castle, paying attention to the following points will lead to a deeper understanding:
- The structure and defensive function of the earthworks
- The relationship between the depth and width of the dry moats
- The layout of the main keep and the second keep
- The size of the castle grounds and the magnitude of the power at the time
- The difference between a fortified residence and a castle
Genealogy of the Ina Clan and the Achievements of Each Generation
First Generation: Ina Tadatsugu
Served Tokugawa Ieyasu and laid the foundation for the position of Kanto Gundai (governor of the Kanto region). He directed large-scale flood control projects, such as the eastward diversion of the Tone River.
Second Generation: Ina Tadamasa
Inherited and further developed his father Tadatsugu’s work.
Third Generation: Ina Tadaharu
Builder of Akayama Castle. He was granted the Akayama territory of 7,000 koku and made this area the new base of the Ina clan.
From the Fourth Generation Onward
For generations, the Ina clan served as regional governors of the Kanto region, dedicating themselves to flood control projects, land reclamation, and disaster relief, contributing to the development of the Kanto area.
Twelfth Generation: Ina Tadataka
The last head of the family. He was dispossessed of his domain due to a family dispute, bringing an end to the Ina family’s history.
Historical Connections to Akayama Castle and its Surroundings
Tone River Diversion Project
One of the largest projects spearheaded by the Ina clan was the diversion of the Tone River. This was a major construction project that changed the course of the Tone River, which once flowed into Tokyo Bay, to its current course towards Choshi. This reduced flooding in Edo and facilitated land reclamation.
Minuma-dai Irrigation Canal
The Minuma-dai Irrigation Canal, an important agricultural water source in Saitama Prefecture, was another project the Ina clan was involved in.
Development of Edo Fukagawa
The Ina clan was also deeply involved in the reclamation and development of the Fukagawa area as Edo’s urban area expanded.
Preservation of Akayama Castle Ruins and Future Challenges
Current Preservation Activities
Saitama Prefecture and Kawaguchi City are actively working to preserve the Akayama Castle Ruins. Efforts are continuing to widely communicate its value as a historical heritage site through the investigation, maintenance, and public access of the remains.
Future Prospects
Parts of the castle ruins are still privately owned or residential, making the preservation of the entire area difficult. However, the main parts have been developed as a park and are open to the public.
Future plans include further research and exploration of the possibility of restoration and maintenance. Utilizing the site as an educational resource and enhancing its appeal as a tourist attraction are also challenges.
Summary
Akayama Castle (Akayama Jinya) is a historically important castle site that served as the base for 163 years for the Ina clan, who were active as the Kanto regional governors during the Edo period. Built on a vast 77-hectare site, this castle lacks a keep and stone walls, but it retains unique remains such as earthworks and dry moats.
The Ina clan made significant contributions to the development of the Kanto region through flood control projects, land reclamation, and disaster relief. Akayama Castle, their base, holds historical significance far beyond mere castle ruins.
Currently, part of the castle site has been developed into a park, and at the Iina Park Kawaguchi Historical and Natural History Museum, visitors can learn about the history of the Ina clan and see a model of the Akayama Jinya (fortified residence). When visiting Kawaguchi City in Saitama Prefecture, be sure to visit this valuable historical site and experience the legacy of the Ina clan, who supported the Kanto region during the Edo period.
While not flashy, Akayama Castle ruins are a valuable cultural asset that quietly conveys the lives of people who played a crucial role in Japanese history.
