The History and Present State of Nerima Castle: From a Branch Castle of the Toshima Clan to a Metropolitan Park – A Castle Ruins in Nerima Ward, Tokyo
Nerima Castle, located in Mukoyama, Nerima Ward, Tokyo, is a valuable historical site within Tokyo, a medieval castle built during the Muromachi period. Currently, following the closure of “Toshimaen” amusement park, it is being reborn as the Tokyo Metropolitan Nerima Castle Ruins Park. This article provides a detailed explanation of the history, structure, and modern transformations of Nerima Castle.
Overview and Location of Nerima Castle
Nerima Castle was a Japanese castle located in Mukoyama, Nerima Ward, Tokyo. It was a flatland castle built on the southern slope of the Shakujii River. It is located near the current Toshimaen Station on the Seibu Ikebukuro Line, and part of the former “Toshimaen” amusement park site corresponds to the castle ruins.
The castle’s location was strategically advantageous, with the Shakujii River, a natural moat, on the north side, and the main defensive facilities located on the plateau to the south. This layout, utilizing the terrain, exhibits typical characteristics of a medieval castle.
Geographical Features
Nerima Castle was built on a tongue-shaped plateau, part of the Musashino Plateau. By utilizing the river terrace formed by the Shakujii River, it functioned as a natural stronghold. This topographical advantage was a crucial element in castle architecture at the time.
In the modern administrative division of Nerima Ward, Tokyo, it corresponds to the Mukoyama area and is accessible from Nerima Station and Toshimaen Station. Its convenient location, easily accessible from central Tokyo, makes it a popular historical site for visitors.
History of Nerima Castle
Construction and the Toshima Clan
The exact construction date of Nerima Castle is unknown, but it is believed to have been built around the end of the 14th century, during the Muromachi period, by the Toshima clan. The Toshima clan was a powerful samurai group in Musashi Province, with Shakujii Castle as their base. Nerima Castle served as a subsidiary castle of Shakujii Castle, playing an important role as a southern defensive stronghold.
The Toshima clan held power in what is now northern Tokyo and southern Saitama Prefecture, and occupied an important position in Musashi Province during the medieval period. Nerima Castle functioned as part of the Toshima clan’s territorial management and defense strategy.
Capture and Fall of Nerima Castle by Ota Dokan
The most important event in the history of Nerima Castle is its fall in 1477. Ota Dokan, the chief retainer of the Ogigayatsu Uesugi clan, attacked the Toshima clan in connection with the Nagao Kageharu Rebellion, and Nerima Castle was captured.
Ota Dokan was a renowned general known for building Edo Castle, and his military talent was highly regarded even then. In the battle against the Toshima clan, Nerima Castle, along with Shakujii Castle, was captured, and the Toshima clan’s power declined significantly.
This battle was one of the events that drastically changed the power dynamics in the Kanto region during the late Muromachi period, and Nerima Castle played a key role in that historical turning point.
Changes After the Fall of the Castle
After its fall, Nerima Castle lost its function as a military base and gradually transformed into farmland and residential areas. During the Edo period, this area became a rural region, and the castle’s remains gradually disappeared.
From the Meiji era onward, as Tokyo’s urbanization progressed, the Nerima area also underwent development, and before the war, the amusement park “Toshimaen” opened. While much of the castle’s remains disappeared due to this development, traces of the past remain in the topography along the Shakujii River.
Structure and Layout of Nerima Castle
Castle Structure
Nerima Castle was built as a flatland castle utilizing a tongue-shaped plateau south of the Shakujii River. It is estimated that the main part of the castle was located south of the Shakujii River, which flows through the current site of “Toshimaen.”
According to pre-war documents, Nerima Castle is believed to have had one of the earliest umadashi (horse-shaped outworks) in Japan. A umadashi is a defensive structure built in front of a castle gate, designed to prevent enemy attacks while facilitating friendly sorties. The presence of this umadashi indicates that Nerima Castle incorporated the latest castle-building techniques of the time.
Defensive System
Nerima Castle’s defensive system skillfully utilized the natural terrain. The Shakujii River, flowing to the north, functioned as a natural moat, and it is believed that earthworks and dry moats were positioned on the plateau to the south.
The castle’s layout was designed to make enemy intrusion difficult by utilizing the meandering of the Shakujii River. Furthermore, it is presumed that the elevation differences of the plateau enhanced the effectiveness of lookouts and defenses.
Existing Remains
Unfortunately, due to its location in the urban area of Nerima Ward, Tokyo, very few remains of Nerima Castle remain due to housing development and urbanization. Currently, only the riverbank elevation along the Shakujii River hints at the castle’s former glory.
Records indicate that parts of the earthworks and moats remained before the war, but these remains were lost due to the opening of Toshimaen amusement park and the development of surrounding residential areas. However, the topography and the flow of the Shakujii River allow us to imagine the layout of the former castle.
Toshimaen and Nerima Castle Ruins
History of Toshimaen
Toshimaen, an amusement park that opened in 1926 (Taisho 15), was built on a portion of the former Nerima Castle site. For approximately 94 years, it was a beloved amusement park for the people of Tokyo, leaving behind many memories.
The name “Toshimaen” originates from the fact that this area was once the territory of the Toshima clan. Records indicate that some remains of the castle were confirmed during the development of the amusement park, making it a place where history and entertainment coexisted.
Closure and New Developments
On August 31, 2020 (Reiwa 2), Toshimaen closed its doors after 94 years of history. The reasons for the park’s closure include aging facilities and changes in the business environment. While the closure was regretted by many, it also raised expectations for a new use of the Nerima Castle site.
After the park’s closure, the site was redeveloped by the Tokyo Metropolitan Government and private companies, with plans for a historical park and new cultural facilities.
The Birth of Tokyo Metropolitan Nerima Castle Ruins Park
Park Overview
On May 1, 2023, Tokyo Metropolitan Nerima Castle Ruins Park opened on a portion of the former Toshimaen amusement park site. This park serves to convey the history of Nerima Castle and is developed as a place of relaxation for local residents.
Within the park, there are information boards explaining the history of Nerima Castle and maps showing the former castle layout, making it a place where visitors can learn about history. Furthermore, the natural environment along the Shakujii River has been preserved, functioning as a valuable green space in an urban area.
Park Features and Facilities
Nerima Castle Ruins Park is designed to balance historical significance with modern park functions. It features plazas, benches, and walking paths, planned as a space for daily use by local residents.
Within the park, information on the history of Nerima Castle will be provided, and regular history lectures and events are planned. This is expected to make it a hub for disseminating the history and culture of Nerima Ward, Tokyo.
Construction of the Harry Potter Facility
Warner Bros. Studio Tour Tokyo
As another major development on the former Toshimaen site, “Warner Bros. Studio Tour Tokyo – The Making of Harry Potter” opened on June 16, 2023. This is a large-scale facility where visitors can experience the world of the “Harry Potter” film series.
This facility was built adjacent to Nerima Castle Ruins Park, creating a unique place where historical heritage and modern entertainment facilities coexist. It is expected to attract many tourists throughout the year and is anticipated to become a new tourist hub in Nerima Ward.
Impact on the Local Community
The opening of the Harry Potter facility has had a significant impact on Nerima Ward’s tourism industry. Commercial facilities and convenience stores around Toshimaen Station and Nerima-Kasugacho Station are being developed to accommodate the increase in tourists.
Furthermore, it is expected that visitors to the facility will also visit Nerima Castle Ruins Park, increasing interest in the area’s history. A new style of tourism, blending history and modern culture, is emerging.
Access and Visiting Information
Transportation Access
Nerima Castle Ruins Park is easily accessible by public transportation. The nearest stations are as follows:
Seibu Ikebukuro Line
- Toshimaen Station: Approximately 1 minute walk
- Nerima Station: Approximately 10 minute walk
Toei Oedo Line
- Toshimaen Station: Approximately 2 minute walk
The facility is very close to Toshimaen Station, located right outside the station. It is also easily accessible from central Tokyo, approximately 10 minutes from Ikebukuro Station on the Seibu Ikebukuro Line.
Nearby Facilities
The following facilities are located near Nerima Castle Ruins Park:
- Warner Bros. Studio Tour Tokyo (Harry Potter facility)
- Shakujii Park (approx. 2km)
- Shakujii Castle Ruins (approx. 2.5km)
- Nerima Art Museum
- Various shopping streets and convenience stores
Visiting these nearby facilities in conjunction with your visit will enhance your sightseeing experience.
Points to Note When Visiting Nerima Castle Ruins Park
The following are points to note when visiting Nerima Castle Ruins Park:
- Check the historical information boards: You can learn about the history and structure of Nerima Castle from the information boards installed in the park.
- Stroll along the Shakujii River: Walking along the river allows you to experience the former castle’s topography. The riverbank elevation changes retain traces of the castle’s former appearance.
- Photography: It’s a good idea to take photos of the park’s scenery and historical information panels for your records.
- Seasonal Changes: The park is designed to allow visitors to enjoy nature throughout the four seasons, making it highly recommended to visit in different seasons.
History and Culture of Nerima Ward
Origins of Nerima Ward
Nerima Ward, Tokyo, is the newest of the 23 wards of Tokyo, established on August 1, 1947 (Showa 22), by separating from Itabashi Ward. It was formed by the integration of the former Kitatoshima District areas of Nerima Town, Kami-Nerima Village, Naka-Arai Village, Shakujii Village, and Oizumi Village.
Nerima Ward is unique among the 23 wards of Tokyo in that it was newly established after the enforcement of the Local Autonomy Law, which defined special wards. Its current population is approximately 750,000, and it is known as a lush, green residential area.
Regional Characteristics
Nerima Ward boasts excellent access to the city center while retaining many green spaces such as farmland and parks. It also has a rich history of agriculture, exemplified by the Nerima radish, and urban agriculture continues to thrive there.
Furthermore, it is known as a hub for the anime industry, with many anime production companies located there. The area around Nerima Station has developed as the central commercial district of the ward, while the areas around Shakujii-koen Station and Egota Station have locally rooted shopping streets.
Nearby Historical Spots
Shakujii Castle Ruins
Shakujii Castle, the main castle of Nerima Castle, was located approximately 2.5 km northwest of Nerima Castle, within the current Shakujii Park. As the base of the Toshima clan, it was larger in scale and a more important strategic point than Nerima Castle.
Shakujii Castle was also captured by Ota Dokan, becoming the stage for the downfall of the Toshima clan. Currently, it is maintained as Shakujii Park, preserving the beautiful natural environment including Sanpoji Pond and Shakujii Pond. There are also information boards about the castle ruins within the park, and visiting both Nerima Castle and Atago Shrine will allow for a deeper understanding of the Toshima clan’s history.
Atago Shrine
Nerima Ward also has shrines and temples associated with the Toshima clan. Atago Shrine and other such sites have a history dating back to the Middle Ages and are still cherished as centers of local faith.
Nerima City Shakujii Park Local History Museum
The museum, located near Shakujii Park, exhibits materials related to the history and culture of Nerima Ward. It also houses materials related to Nerima Castle and Shakujii Castle, allowing visitors to obtain more detailed information.
Materials and Research on Nerima Castle
Historical Materials
While historical materials on Nerima Castle are limited, the existence and history of the castle can be confirmed from the following historical documents:
- “Ota Dokan-jo”: A historical document recording the battle achievements of Ota Dokan
- “Kamakura Ososhi”: A military chronicle describing the Sengoku period in the Kanto region
- Edo period geographical records and maps
These materials confirm that Nerima Castle functioned as a branch castle of the Toshima clan and fell in Bunmei 9 (1477).
Archaeological Investigation
While there are records of remains being confirmed at part of the Nerima Castle site before the war, detailed archaeological investigations have not been sufficiently conducted. Currently, opportunities for excavation are limited due to urbanization, but there is a possibility of new discoveries as part of future redevelopment.
During the development of Nerima Castle Ruins Park, historical investigations were conducted to the extent possible, and the results were utilized in the park’s design and guidance.
Research Books and Information Sources
The following are resources for learning about Nerima Castle:
- Nerima Ward History
- Research books on medieval castles in Tokyo
- Historical books on the Toshima clan
- Biographies and research books on Ota Dokan
These books can be viewed at the Nerima Ward Library and the Tokyo Metropolitan Library. Information on Nerima Castle can also be found online on castle information websites such as Kojodan.
Cultural Value of Nerima Castle
Medieval Castles in Tokyo
Many medieval castles have been lost due to urbanization in Tokyo, particularly within the 23 wards. Nerima Castle is a valuable example of a castle for which relatively good information has been preserved.
Other medieval castles in Tokyo include Edo Castle, Shakujii Castle, and Akatsuka Castle, but most of their remains have been lost. Learning about the history of Nerima Castle is of great importance for understanding Tokyo’s medieval history.
Regional Identity
Nerima Castle is an important element of Nerima Ward’s historical identity. Just as the name “Toshimaen” (a theme park) retains the name of the Toshima clan, the memory of the castle has been passed down within the local historical consciousness.
The development of Nerima Castle Ruins Park revives this historical memory in the modern age, providing an opportunity for local residents to re-examine their own history. The park is also expected to play an important role as a place for historical education.
Value as a Tourism Resource
The combination of Nerima Castle Ruins Park and the Harry Potter facility represents a new tourism model that fuses historical tourism with modern entertainment.
For international tourists, it holds unique appeal as a place where they can learn about Japan’s medieval history while enjoying modern facilities. It holds the potential for Nerima Ward in Tokyo to develop into a new tourist hub.
Summary: From Past to Future
Nerima Castle is a medieval castle built by the Toshima clan at the end of the 14th century and captured by Ota Dokan in the late 15th century. After many years, it became an amusement park called “Toshimaen,” which was popular with many people.
After Toshimaen closed in 2020, the site was redeveloped as Nerima Castle Ruins Park and the Harry Potter facility, reborn as a new place where history and modern culture coexist. The history of Nerima Castle will continue to be passed down as part of the identity of Nerima Ward in Tokyo.
The flow of the Shakujii River and the topography of the plateau still convey the remnants of a castle from over 600 years ago. A visit to Nerima Castle Ruins Park allows you to feel the layers of history within the heart of the city. For history enthusiasts, local residents, and tourists alike, Nerima Castle Ruins is a place to discover the diverse charms of Tokyo.
Located in the heart of Nerima Ward and easily accessible, Nerima Castle Ruins Park will likely be used by many people as a starting point for historical walks and as a place of daily relaxation. The story of this land, spanning from the time of the Toshima clan and Ota Dokan to the present day, teaches visitors about Tokyo’s rich history.
