Adventure to the Impregnable Castle, “Kanayama Castle”

“Kanayama Castle” is a mountain castle built in the first year of the Bunmei era (1469). Despite enduring numerous attacks from figures such as Uesugi Kenshin and Takeda Katsuyori, it has never allowed enemy infiltration, earning its reputation as an impregnable mountain castle. Traces of facilities like earthen walls and moats still exist, leading to its inclusion in Japan’s list of the Top 100 Castles.
This time, I plan to hike through the Kanayama Hills and explore historical sites along the way.
Guidance Facilities for the Historical Site of Kanayama Castle
First, to gather information, I visited the guidance facilities at the historical site of Kanayama Castle.

Admission is free, and the facility showcases a detailed story supported by a model of Kanayama Castle, artifacts, and excerpts from diaries of that era.


While photography is restricted in some areas, I can’t share images, but the exhibition is filled with exciting and intriguing information.
Commencing the Journey from Daikoin
Parked the car at the Daikoin parking lot and began the adventure. Heading towards the main enclosure via the Nishiyama Trail.
After a bit of climbing, reached the peak where the stone monument “Historical Site of Kanayama Castle Slope” comes into view.

Mitsuke Demaru (見附出丸)
Moving along the ridge towards the main enclosure, I encountered a moat.

A moat serves as a defensive structure to impede the enemy’s progress and narrow down their movement during battles.
Beyond the moat is an area known as “Mitsuke Demaru,” where watchtowers were stationed to guard the western side of the castle.

From Mitsuke Demaru, you can oversee the moat from a slightly elevated position, allowing for better control over potential adversaries.

It is believed that fences were installed around the earthen walls to secure the perimeter.

Nishi-shiro (西城)
Enemy soldiers who breach Mitsuke Demaru proceed towards the Western Castle. The area above the current motor pool is the Western Castle.

To impede enemy soldiers attacking the Western Castle, there is the Mitsuke Trench. The use of the term “trench” instead of “moat” suggests it might have been a facility designed not only to impede enemy movement but also to counterattack while defending against projectiles.

Boardwalk and the western side of the arrow warehouse platform.
Continuing along the ridge from the Western Castle leads to a boardwalk.

In times of emergency, the boardwalk was constructed in a simple manner, allowing for easy destruction to impede progress. Further ahead, one encounters the Nishiyagura-dai Nishi-Horikiri, another structure designed to obstruct movement.

From Nishiyagura-dai, you can overlook the trench and launch one-sided attacks effectively.


Gate entrance (虎口)

It’s said that a “tiger’s mouth” (toraguchi) intentionally narrows the entrance to weaken the enemy’s momentum. Moreover, the practical aspects include creating bends in the passage or obstructing the view at the end of the tiger’s mouth. In the upper left, there is an observation platform, providing the opportunity to attack the heads of enemy soldiers bottlenecked in the tiger’s mouth.

On the left side, there is an impressive trench. It resembles more of a stone quarry than a traditional moat.
Traces of the horse-riding bailey (馬場曲輪址) and the large moat cut (大堀切).
It is said that soldiers were stationed at the Babakuruwa to guard the tiger’s mouth.

Once you breach this point, you reach the Ote Toraguchi, the main entrance. But before that, there is the largest trench of Kanayama Castle, the O-horikiri, which serves as a formidable obstacle against enemy advancement.

Main gate entrance (大手虎口)

The highlight of Kanayama Castle, the Ote Toraguchi. With elevated terrain on both sides, it exudes a commanding presence.

As you move deeper into the main passage, it narrows, creating an optical illusion of a longer pathway. Additionally, a gentle right curve obstructs the view, adding to the mystery. Creating water channels on both sides enhanced drainage, and measures were taken to prevent the erosion of stone walls.

Hinoike
Kanayama Castle features two ponds, known as Hinoike (Sun Pond) and Tsukinoike (Moon Pond).

Hinoniike is a rare large pond atop the mountain, serving as a symbolic location within Kanayama Castle. It is believed to have been used for daily water needs and ceremonies such as celebrations of victory or rain-making rituals. Artifacts from the Heian period related to water worship have been discovered, indicating that it was a sacred place even before the castle’s construction.
The 800-Year-Old Giant Keyaki Tree

The towering giant keyaki tree in Gotaidokoro is said to be 800 years old. Considering the construction of Kanayama Castle in 1469, it implies that the tree has been standing in this location for more than 200 years before the castle was built. It stands as a living witness to the entire history of Kanayama Castle.
Main castle keep.

In the main enclosure, there is Nitta Shrine and its office.
Regarding the artillery shell, it’s difficult to determine without additional context or visual information. If you could provide more details or describe the characteristics of the projectile, I might be able to offer more insight.

View from the main castle keep.

Bailey for rapid movement (武者走り) and the site of the stables.

The eastern side one level below the main castle keep is called “Musha-bashiri,” which is a belt-shaped bailey. The soldier’s quick movement is made possible by this belt-shaped bailey.

Proceeding along the “Musha-bashiri” towards the rear of the main castle keep, you will find the site of the stables. Horses being sensitive animals, the stables were placed in the quiet area behind the main castle keep. Indeed, it remains a tranquil place with little popularity even today.
Remaining stone walls of the main castle keep.

Behind the main castle keep, next to the stable area, there are remnants of stone walls from Kanayama Castle. While most of Kanayama Castle’s stone walls have been reconstructed, the original stone walls from that time remain in two locations: behind the main castle keep and on the south side of the southern bailey.
Compare the “元禄太田金山絵図” with the current topographic map.
By examining the “元禄太田金山絵図” which is also displayed at the historical site Kanayama Castle Guidance Facility, you can gain a better understanding of the original topography of Ota Kanayama Castle.

The illustration, created by the artist Takase in the year 1701, provides a nearly accurate representation of the terrain during that time, being drawn 111 years after the abandonment of Kanayama Castle. When compared to the current topographic map, a high degree of accuracy and correlation can be observed. For instance, the positions of Oyaji-san, Naka-hachi-oji-san, Kumano Shrine, and the reservoir align closely between the two depictions.


Personally, I am curious about the route of the “Ote-michi” (main entrance path). Currently, to access Kanayama Castle, one would take the Kanayama Castle Site Line, but this road is not the original route. There is a mountain trail on the southern side, but its location differs from the path shown in the illustrated map.
I would like to know about the main entrance path of Kanayama Castle. Looking at the illustrated map, there should be a direct route from the guidance facility to the Ote-toraguchi (main gate). If we were to create a path, where would it be? I tried drawing two lines on the topographic map while considering the terrain.

The red line represents the path passing through the samurai residence heritage site behind the guidance facility. However, it seems too steep, so I also drew another route with the blue line. Considering the location of the Ote-toraguchi, I believe there might have been a path around the area where I drew the lines.
As for the 16th curve on the Kanayama Castle Site Line, which has been under excavation for over a decade, it is uncertain when the excavation survey will be completed.
Conclusion
The remains of Kanayama Castle are an irresistible spot for enthusiasts of mountain castles. Walking through the site allows you to vividly imagine the scenes of battles and the daily lives of the people from that era. Moreover, the rich natural surroundings provide an opportunity for enjoyable hiking.
Kanayama Castle Site is a place where you can discover new charms with each visit. It’s a spot filled with the allure of history, nature, and the satisfaction of exploration.
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