Complete Guide to Banshinzan Castle (Minato Ward) | The History from Ota Dokan’s Edo Castle Outpost to Sengokuyama
A castle once stood in the vicinity of Roppongi 1-chome, Minato Ward, Tokyo. While today a prime location in the heart of the city with towering skyscrapers, this site holds a rich history spanning from the Muromachi period to the Edo period and beyond. This article provides a detailed explanation of Banshinzan Castle, from its historical background to its current state.
What is Banshinzan Castle? | An Outpost of Edo Castle Built by Ota Dokan
Banshinzan Castle was built in the mid-Muromachi period by Ota Dokan, a retainer of the Ogigayatsu Uesugi family, the Kanto Kanrei (governor of the Kanto region). It functioned as an outpost (branch castle) of Edo Castle and is also known as “Ota Dokan Castle.”
Background of the Castle’s Construction by Ota Dokan
Ota Dokan was a renowned general of the Sengoku period, known for constructing Edo Castle in 1457 (Choroku 1). When building a defense network centered around Edo Castle, he placed several outposts at key locations in the surrounding area. Banshinzan Castle was one of these, a crucial base protecting the southwestern side of Edo Castle.
The reason this location was chosen was its geographical advantage: it was a high ground at the southern edge of the Musashino Plateau, offering a panoramic view. From a military perspective, it is believed to have played a role in monitoring enemy movements from the direction of Edo Bay (present-day Tokyo Bay) and transmitting information to the main Edo Castle.
Origin of the Name of Banshinzan Castle
There are several theories regarding the origin of the name “Banshinzan,” but the most plausible theory is that it derives from the presence of a shrine dedicated to Banshin (the Thirty Guardian Deities) in this area. Banshin worship involves the worship of thirty deities who protect the Lotus Sutra, and was widely practiced among the samurai class in the medieval period. Ota Dokan is also said to have been a devout follower of the Nichiren sect of Buddhism, and it is believed that the name of the castle remains from the fact that he enshrined a guardian deity there.
Structure and Scale of Banshinyama Castle
Basic Structure of the Castle
According to records that remained until the Meiji era, Banshinyama Castle had a structure mainly composed of earthworks. It is said to have possessed the characteristics of a typical medieval flatland castle, without the use of stone walls.
Specific structural features are described in historical documents as follows:
- Earthworks: Earthworks were built as defensive structures surrounding the castle.
- Dry Moat: It is highly likely that a dry moat was dug outside the earthworks.
- Enclosures: It is presumed that the castle had a structure with multiple enclosures (sections).
- Gate Entrance: A gate entrance was provided to the castle.
Scope of the Castle Area
There are various theories regarding the exact scope of the castle area, but it is believed that the area centered around the current Ark Hills Sengokuyama Mori Tower was the castle area. Located on a hill approximately 25 meters above sea level, it functioned as a defensive structure utilizing the difference in elevation from the surrounding area.
Changes in the Edo Period | To the Residence of the Sengoku Family of Izushi Domain
The End of the Sengoku Period and the Changing Role of Castles
After the death of Ota Dokan, the Kanto region came under the control of the Later Hojo clan, and Banshinzan Castle ceased to serve its military role. Following Toyotomi Hideyoshi’s siege of Odawara in 1590 (Tensho 18), when Tokugawa Ieyasu entered Edo, this area was developed as part of the Edo city-building project.
Establishment of the Sengoku Family Residence of Izushi Domain
In the Edo period, the Edo residence of the Sengoku family of the Izushi Domain in Tajima Province (present-day Hyogo Prefecture) was established on the site of Banshinzan Castle. The Sengoku family was a daimyo family ruling over 58,000 koku, and they were granted this hilltop, the former castle site, as their residence in Edo.
The Sengoku family established their residence in this area, and the surrounding region came to be known as “Sengokuyama.” This name is still used as a local nickname and is known as a place name that doesn’t appear on maps.
History and Characteristics of the Sengoku Family
The Sengoku family was a daimyo family descended from Sengoku Hidehisa. Hidehisa served as a retainer of Toyotomi Hideyoshi and was granted the Komoro Domain in Shinano Province after the Siege of Odawara. After various twists and turns, they became the lords of the Izushi Domain in Tajima Province, a position they held until the Meiji Restoration.
Throughout the Edo period, the Sengokuyama residence served as the Sengoku family’s political and social center in Edo. Other daimyo residences lined the area, making it a prestigious district developed as a samurai residential area.
Changes Since the Meiji Era | From Aristocratic Residences to Imperial Residences
The Meiji Restoration and the Aristocratic System
After the Meiji Restoration, daimyo families were positioned as noble families, and the Sengoku family continued to exist as the noble Sengoku family. Records indicate that castle remains, such as earthworks, remained on this site until the early Meiji period, but these gradually disappeared amidst the wave of modernization.
The Residence of the Higashikuni-no-miya Family
From the Taisho era to the early Showa era, this site became the residence of the Higashikuni-no-miya family, a member of the imperial family. Prince Higashikuni Naruhiko is also known for later serving as Prime Minister immediately after the end of World War II. The presence of an imperial residence further strengthened the character of the Sengokuyama area as a prestigious region.
Post-War Development and Residentialization
After World War II, this area gradually developed into a residential area. Due to its topographical features as a hilltop and its historical significance, it developed into a high-class residential area. The strong ground is one of the major characteristics of this area.
Current Banshinzan Castle Ruins | Ark Hills Sengokuyama Mori Tower
Redevelopment by Mori Building
In 2012, the “Ark Hills Sengokuyama Mori Tower” was born on this historic site. As part of Mori Building’s “Toranomon-Roppongi District Type 1 Urban Redevelopment Project,” it is a mixed-use skyscraper constructed with a total project cost of approximately 65.6 billion yen.
Overview of Ark Hills Sengokuyama Mori Tower
- Location: 1-9 Roppongi, Minato-ku, Tokyo
- Structure: Reinforced concrete, partially steel frame
- Scale: 47 floors above ground, 4 floors below ground
- Height: Approximately 200 meters
- Usage: Residential (Ark Hills Sengokuyama Residence), offices, commercial facilities
- Completion: August 2012
Concept of “Vertical Garden City”
Based on Mori Building’s concept of a “Vertical Green City,” the building integrates mixed-use facilities within a skyscraper, creating plazas and green spaces on the ground level. This can be seen as an attempt to pass on the historically rich green environment of this area to the present day.
Sengokuyama Stone Monument
Even today, a stone monument inscribed with “Sengokuyama” remains at the castle site. This monument is a valuable historical site that conveys the history of this area, which has continued since the Edo period, to the present day. Visitors can sense the layered history of this site through this monument, recognizing that a castle, a daimyo’s residence, and a royal residence once stood here.
Banshinzan Castle Highlights and Visitor Guide
Existing Remains
Unfortunately, the remains of Banshinzan Castle are now completely lost, and it is impossible to see earthworks or moats. Records indicate that earthworks remained until the Meiji era, but they disappeared with the progress of urbanization.
Points of Interest During Your Visit
Although no remains of the castle exist, you can experience history at the following points:
- Sengokuyama Stone Monument: A stone monument that conveys memories of the Edo period.
- Observing the Topography: Understanding the former military importance from its elevated location.
- Surrounding Green Spaces: The green spaces developed around Ark Hills Sengokuyama Mori Tower retain the atmosphere of the former samurai residences.
- Shiroyama Greenway: Experiencing the historical environment of the area by walking along the nearby greenway.
Nearby Historical Spots
When visiting the Banshinzan Castle Ruins, we recommend also visiting the surrounding historical spots:
- Akasaka Hikawa Shrine: A prestigious shrine built by Tokugawa Yoshimune.
- Hotel Okura: A historic luxury hotel that symbolizes the prestige of the surrounding area.
- Toranomon Hills: A recently developed complex where you can experience both old and new Tokyo.
- Edo Castle (Imperial Palace): Edo Castle, the main castle of Banshinzan Castle, is also within walking distance.
Access Information
Access by Train
The following stations can be used to reach Banshinzan Castle Ruins (Ark Hills Sengokuyama Mori Tower):
- Tokyo Metro Namboku Line “Roppongi-itchome Station”: 4-5 minute walk (nearest station)
- Tokyo Metro Hibiya Line “Kamiyacho Station”: 7 minute walk
- Tokyo Metro Ginza Line/Namboku Line “Tameike-Sanno Station”: 8 minute walk
- Toei Oedo Line/Tokyo Metro Hibiya Line “Roppongi Station”: 10 minute walk
Access from Roppongi-itchome Station is the most convenient, and you can arrive in just a few minutes on foot from the station.
Access by Car
Approximately 5 minutes from the Shuto Expressway Inner Ring Line “Kasumigaseki IC” or “Iikura IC”. However, the Ark Hills Sengokuyama Mori Tower parking lot is for residents and tenants only, so general visitors are advised to use public transportation. ### Points to Note When Visiting
- As the site is currently a mixed-use building with residential, office, and commercial facilities, respect for residents’ privacy is necessary.
- The Sengokuyama monument is located in a public area, but it is recommended to confirm its exact location in advance.
- When taking photographs, please be considerate of local residents and passersby.
Historical Significance of Banshinzan Castle
Role in the Edo Castle Defense Network
Banshinzan Castle played an important role in the defense network centered around Edo Castle, as envisioned by Ota Dokan. It is believed to have functioned as a monitoring and defensive base against threats from the southwest of Edo Castle, particularly from the direction of Edo Bay.
The Kanto region in the late Muromachi period was in a complex political situation, with conflicts between the Koga Kubo and the Kanto Kanrei, as well as the rise of the Later Hojo clan. In this context, Edo Castle and its network of outposts were essential military facilities for maintaining the power of the Ogigayatsu Uesugi family.
Value of “Sengokuyama” as a Place Name
Currently, “Sengokuyama” is not an official place name and does not appear on maps. However, this name is still widely used among local residents and in the real estate industry. This “place name not found on maps” symbolizes the memory and pride of the land, a legacy dating back to the Edo period.
The name “Sengokuyama,” which holds brand value as a high-end residential area, is based on the historical fact that it was the site of the residence of the Sengoku family, the feudal lords of the Izushi Domain. This accumulation of history can be said to give cultural depth to the modern urban space.
Challenges of Urban Development and Historical Preservation
The case of Banshinzan Castle raises the modern challenge of balancing urban development and the preservation of historical heritage. While earthworks remained until the Meiji era, they have now completely disappeared.
On the other hand, the development of Ark Hills Sengokuyama Mori Tower attempts to preserve the memory of the land by using the historical name “Sengokuyama.” Furthermore, the creation of green spaces demonstrates an effort to recreate the environment of the former samurai residence era in a modern form.
Castles Associated with Ota Dokan
To understand Banshinzan Castle, knowing about other castles built by Ota Dokan will provide a deeper understanding.
Edo Castle
This was the main castle built by Ota Dokan in 1457. Located where the current Imperial Palace stands, it was extensively expanded during the Edo period as the residence of the Tokugawa shogunate. Banshinzan Castle functioned as an outpost of Edo Castle.
Kawagoe Castle
Located in Kawagoe City, Saitama Prefecture, this castle is believed to have been built by Ota Dokan. It was one of the important strongholds of the Ogigayatsu Uesugi clan.
Iwatsuki Castle
Located in Iwatsuki Ward, Saitama City, Saitama Prefecture, this castle is also believed to have been built by Ota Dokan. It was a strategic point protecting the north of Edo Castle.
These castles formed part of a wide-area defense network envisioned by Ota Dokan. Banshinzan Castle also played an important role in this strategic arrangement.
Castle Historical Sites in Minato Ward
In addition to Banshinzan Castle, several other historical castle-related sites exist in Minato Ward, Tokyo.
Toranomon Area
This area was home to Toranomon, one of the outer gates of Edo Castle. While currently undergoing redevelopment such as Toranomon Hills, it retains its history as a castle town of Edo.
Akasaka Area
This area was lined with daimyo residences during the Edo period, and historical buildings such as Akasaka Hikawa Shrine remain. Similar to the Banshinzan Castle ruins, it had the characteristics of a samurai district.
Shiba Area
This temple town, centered around Zojoji Temple, flourished as the family temple of the Tokugawa shogunate. It also served as a religious and military base protecting the southern part of Edo Castle.
Resources for Learning About Banshinzan Castle
For those who wish to learn more about Banshinzan Castle, we introduce some helpful resources.
Documentary Resources
- Historical books related to “Ota Dokan”
- Research books on “Edo Castle and its Surroundings”
- Local history materials of Minato Ward
- Historical materials related to the “Sengoku Family of Izushi Domain”
Digital Resources
- Castle information websites such as Kojodan
- National Diet Library Digital Collection (old maps, etc.)
- Minato Ward Local History Museum website
On-site Information Gathering
- Exhibits at the Minato Ward Local History Museum
- Signboards and explanatory signs in the surrounding area
- Local historical walking tours (sometimes held regularly)
Summary | Historical Memories Continuing from Lost Castles
Banshinzan Castle began as an outpost of Edo Castle built by Ota Dokan during the Muromachi period. During the Edo period, it served as the residence of the Sengoku family of the Izushi Domain, and from the Meiji era onward, as a residence for the nobility and imperial family. While changing its appearance with each era, it has always existed as a place of high status.
Although the castle ruins have now completely disappeared and the area is now a prime location in the heart of Tokyo with skyscrapers, the name “Sengokuyama” and the stone monument still convey the rich history of this place to the present day. This place name, which doesn’t appear on maps, will continue to be passed down as a symbol of the memories and pride etched into the land.
When visiting Minato Ward in Tokyo, be sure to visit the Banshinzan Castle ruins and feel the layers of history that breathe life into this modern urban space. Looking out from the hilltop, you’ll understand why Ota Dokan chose this location. Despite being in the heart of the city, the lush green environment still conveys the atmosphere of the former samurai residence era.
The history of Banshinzan Castle symbolizes the layered accumulation of time that the city of Tokyo possesses. By imagining the lives of people that have continued from the Muromachi period to the present day beyond the lost ruins, we can feel history more intimately close.
