Izumi Castle (Kasama City, Ibaraki Prefecture) Complete Guide | A Thorough Explanation of the History, Remains, and Access to Shōtenzan Castle
Izumi Castle, located in Izumi, Kasama City, Ibaraki Prefecture, is a medieval mountain castle also known as “Shōtenzan Castle” or “Kami no Shiro” (Upper Castle). Built on the eastern foothills of Mt. Shōtenzan (218m above sea level), this castle is a valuable historical site that preserves the castle culture of Hitachi Province from the Nanboku-chō period to the Muromachi period, attracting attention from castle enthusiasts and history buffs.
This article thoroughly explains the charm of this little-known mountain castle, covering its historical background, castle structure, remains that can be seen on-site, points of interest for visitors, and access methods.
Basic Information on Izumi Castle
Location: Izumi, Kasama City, Ibaraki Prefecture
Alternate Names: Kanekotoyama Castle, Kami Castle
Castle Classification: Mountain Castle
Construction Period: Nanboku-cho period to Muromachi period
Builder: Shishido clan
Elevation: 218m (Relative height approximately 110m)
Main Remains: Earthworks, baileys, moats
Nearest Station: Iwama Station, JR Joban Line (approximately 2.4km southwest)
Currently, part of the castle site is used for communication facilities and forestry, giving it a different atmosphere from typical tourist destinations. However, with appropriate equipment and knowledge, it is a place where you can fully experience the charm of a medieval castle.
History and Construction Background of Izumi Castle
The Shishido Clan and the Medieval Situation of Hitachi Province
The Shishido clan, who are believed to have built Izumi Castle, were one of the leading medieval samurai groups in Hitachi Province. The Shishido clan held power in this region from the late Heian period to the Kamakura period, and records show they were active on the side of the Southern Court during the Nanboku-cho period.
The area around Kasama City, Ibaraki Prefecture, was a strategically important region in the medieval period, serving as a crucial transportation hub connecting Mito and Kasama, and located in the central part of Hitachi Province. Izumi Castle is thought to have functioned as one of the Shishido clan’s key castles, given this geopolitical background.
Role from the Nanboku-cho Period to the Muromachi Period
During the Nanboku-cho period (1336-1392), Hitachi Province was a fierce battleground where the forces of the Northern and Southern Courts were evenly matched. The Shishido clan sided with the Southern Court, and it is presumed that Izumi Castle functioned as their military base. Located at an altitude of 218 meters, Izumi Castle offered a wide vantage point overlooking the surrounding area, making it ideal for monitoring enemy movements.
During the Muromachi period, the Kanto region experienced complex political situations, including the conflict between the Kamakura Shogunate and the Kanto Kanrei Uesugi clan, and the establishment of the Koga Shogunate. Izumi Castle, as a fortress that survived these turbulent times, witnessed the history of the region.
Changes After the Sengoku Period
During the Sengoku period, the Satake clan gradually expanded its power in Hitachi Province. The Shishido clan deepened their relationship with the Satake clan and eventually came under their control. While historical records are limited regarding the role Izumi Castle played during this process, it has been suggested that it may have already been abandoned by the Sengoku period.
In the Edo period, the Kasama Domain was established, and Kasama Castle became the center of the region. Izumi Castle completed its historical role and returned to forest.
Layout and Structure of Izumi Castle
Location and Topographical Features
Izumi Castle was built on Kanekoroyama, an isolated peak with an elevation of 218m located in the northern part of the Izumi district of Kasama City. Its relative height of approximately 110m is considered medium-sized for a mountain castle in the Kanto region, but it provides sufficient defensive capabilities from the surrounding plains.
The mountaintop is relatively flat, with a long, narrow ridge extending east and west. Multiple baileys (enclosures) were cleverly arranged, utilizing this terrain. Even today, walking near the mountaintop reveals artificially leveled surfaces.
Arrangement of Main and Secondary Enclosures
The main enclosure (honmaru) of Izumi Castle is believed to have been located on the summit of Kanekoroyama. While some remains have been altered due to the construction of communication facilities, traces of earthworks and steep slopes remain in the surrounding area.
To the east of the main enclosure, several secondary enclosures (such as the second and third baileys) were arranged in a stepped fashion. This is a typical “renkukashiki” (連垣式) layout for mountain castles, designed so that the enemy would have to break through multiple lines of defense before reaching the main enclosure.
Remains of Earthworks and Moats
The greatest highlight of Izumi Castle is the remaining remains of earthworks and moats.
Earthworks: Earthworks, approximately 1-2 meters high, remain partially around the main enclosure. These earthworks served to prevent enemy intrusion and enhanced defensive capabilities by allowing for the construction of fences and walls on top. The earthworks of Izumi Castle exhibit a typical structure of medieval castles and are valuable resources for understanding the castle-building techniques of the time.
Moats: Moats, dug to cut off the ridgeline, are important defensive structures in mountain castles. At Izumi Castle, a moat is believed to have been located behind the main enclosure (to the west), and traces of it can still be seen today. Moats not only physically hindered enemy intrusion but also functioned as a psychological barrier.
Arrangement and Function of the Enclosures (Kuruwa)
The castle grounds consisted of several enclosures of varying sizes. Each enclosure is presumed to have had the following functions:
- Main Enclosure: The central area where the lord’s residence and command post were located.
- Secondary Enclosure: Used as a soldiers’ quarters and armory.
- Waist Enclosure: A small enclosure surrounding the main enclosure, reinforcing its defenses.
- Eastern Foothills: Possibly the location of a residence or storage facility for supplies during peacetime.
Highlights and Visiting Guide to Izumi Castle
Remains Observable on Site
This section specifically introduces the remains to be noticed when visiting Izumi Castle.
1. Earthworks around the Main Enclosure
Careful observation around the communication facilities reveals traces of artificially constructed earthworks. Parts on the north and east sides, in particular, remain in relatively good condition.
2. Flat Surfaces of the Leveled Enclosures
From the mountaintop to the east, you can see the flat surfaces of the enclosures arranged in a stepped pattern. These artificially flat surfaces, clearly different from the natural terrain, are a point where you can truly appreciate the medieval castle-building techniques.
3. Traces of Cut Slopes
Steep slopes (cut slopes) are provided between the enclosures. This was a design intended to make enemy movement difficult, and experiencing the elevation difference firsthand helps to understand the defensive thinking of the time.
4. Traces of Moats
Traces of moats remain on the ridge behind the main enclosure. Although largely buried, careful observation reveals traces of artificial excavation.
Ascent Route and Time Required
The most common route to Izumi Castle is the one that ascends along the ridge from the eastern foot of the mountain.
Route to the Castle:
- From the village of Izumi in Kasama City, Ibaraki Prefecture, take the hiking trail.
- Climb the eastern ridge for approximately 30-40 minutes.
- Reach the main enclosure via the secondary enclosures.
Estimated Time: Approximately 1 hour to 1 hour 30 minutes round trip.
Difficulty: Intermediate (suitable for those familiar with mountain trails).
Notes for Visitors
Izumi Castle is not a well-maintained tourist destination, so the following preparations and precautions are necessary for a visit.
- Clothing: Long-sleeved shirt, long pants, and trekking shoes are essential.
- Equipment: Drinking water, map, compass (or GPS), insect repellent spray.
- Season: Spring to autumn is the best time to visit. Snowfall is possible during winter.
- Avoid traveling alone: Visiting in a group is preferable if possible.
- Respect for private property: Some areas may be private property, so please observe proper etiquette.
Access and surrounding information
Access by public transport
Nearest station: JR Joban Line, Iwama Station
Distance from station: Approximately 2.4km southwest
Travel time: Approximately 30-40 minutes on foot
Access from Iwama Station to Izumijo Castle is mainly on foot. Taxis are available from the station, but the number is limited, so it is recommended to check in advance.
Also, Tomobe Station on the JR Joban Line is relatively close, approximately 4km away.
Access by Car
Joban Expressway:
- Approximately 10 minutes from Iwama IC
- Approximately 15 minutes from Tomobe IC
Kita-Kanto Expressway:
- Approximately 20 minutes from Kasama-Nishi IC
Regarding parking, there is no official parking space around the castle ruins. Please avoid street parking to avoid inconveniencing local residents, and consider using nearby public facilities.
Surrounding Castles and Historical Sites
Many medieval castles are scattered around Kasama City, Ibaraki Prefecture, in addition to Izumi Castle.
Kasama Castle: A representative castle of Kasama City. Built by Kasama Tokitomo during the Kamakura period and used until the Edo period. Located near Kasama Inari Shrine, remnants of stone walls and turrets remain.
Nandaiyama Castle: A mountain castle located near the border of Kasama City and Mito City. A castle closely associated with the Satake clan.
Tategishi Castle: A flatland castle located within Kasama City. This is one of the castles associated with the Shishido clan.
Visiting these castles in combination will allow you to gain a deeper understanding of the overall picture of medieval castles in Hitachi Province.
Kasama City Tourist Spots
Here are some tourist spots in Kasama City that you might want to visit between castle explorations.
Kasama Inari Shrine: An ancient shrine counted as one of Japan’s three major Inari shrines. It is bustling with many worshippers throughout the year.
Kasama Art Forest Park: A park themed around pottery. It includes the Ibaraki Prefectural Ceramic Art Museum and Kasama Craft Hill.
Kitayama Park: A beautiful lake selected as one of Ibaraki Prefecture’s Top 100 Tourist Spots. It is ideal for hiking.
Kasama Pottery Festival: A pottery market held annually during Golden Week. Potters from all over Japan gather here.
Historical Sites Related to Izumi Castle and the Shishido Clan
The Shishido Clan’s Base and Network of Branch Castles
The Shishido clan built several castles around Kasama City, solidifying their territory. Izumi Castle is thought to have been part of this network of branch castles.
While there are various theories regarding the Shishido clan’s base, Shishido Castle (present-day Shishido area of Kasama City) is believed to have played a central role. Izumi Castle is located approximately 5 km north of there and may have functioned as a defensive base to the north.
The Relationship Between the Shishido and Satake Clans
During the Sengoku period, the Shishido and Satake clans, who became the rulers of Hitachi Province, maintained close ties, including marriage alliances. The Shishido clan, in particular, played an important role as a powerful branch of the Satake clan and continued to exist as samurai of the Akita Domain during the Edo period.
Understanding this historical background helps us understand that Izumi Castle was not merely a small local castle, but functioned as part of the political and military network of Hitachi Province.
Research and Preservation Status of Izumi Castle
Current Status of Academic Research
While detailed archaeological excavations have not been conducted on Izumi Castle, surveys and the creation of layout maps are underway by castle researchers. Websites such as “Castle Wanderings” and records kept by local history research societies are particularly contributing to understanding the true nature of Izumi Castle.
Future detailed surveys and the excavation of historical documents are expected to shed light on the construction date, specific period of use, and changes in castle lords of Izumi Castle.
Preservation Status and Challenges of the Remains
Currently, some of the remains of Izumi Castle have been altered due to the use of the area as forest and for communication facilities. However, the main remains are preserved in relatively good condition, conveying the appearance of a medieval mountain castle.
Future challenges include the following:
- Detailed documentation of the remains and formulation of a preservation plan
- Improvement and safety measures for the castle access route
- Provision of information through the installation of signboards and explanatory panels
- Preservation activities in cooperation with local residents
As a valuable historical heritage site of the region, it is necessary to strike a balance between appropriate preservation and utilization.
Significance of Visiting Izumi Castle
Experiencing the Original Landscape of a Medieval Castle
The greatest charm of Izumi Castle lies in the fact that, because it has not been excessively developed, you can experience the “original landscape” of a medieval mountain castle. Unlike castles that have been turned into tourist destinations, you can feel the spirit of the people of that time from the remains that stand quietly in nature.
Walking along the earthworks, confirming the layout of the enclosures, and feeling the depth of the moats—through these experiences, you can gain a real sense of history that you cannot learn from textbooks, which is the real pleasure of visiting Izumi Castle.
Deepening Understanding of Local History
Visiting Izumi Castle provides an opportunity to gain a deeper understanding of the local history of Kasama City, Ibaraki Prefecture. What was the political situation in Hitachi Province during the Middle Ages? What role did the Shishido clan play? And how has the Kasama region changed throughout history?
By confronting these questions, you can experience the joy of intellectual exploration that goes beyond mere sightseeing.
Contribution to Castle Research
Small and medium-sized castles in rural areas, like Izumi Castle, are still an under-researched field. Recording observations, taking photographs, and sharing information by visitors contributes to the advancement of castle research.
Websites such as “Kojodan” (Castle Attack Group) actively facilitate information sharing among visitors, and such grassroots activities support castle research in Japan.
Summary: The Charm and Future Prospects of Izumi Castle
Izumi Castle (Kanekoroyama Castle), located in Izumi, Kasama City, Ibaraki Prefecture, is a mountain castle built by the Shishido clan during the Nanboku-cho and Muromachi periods. Built on Mt. Kanekoro, at an elevation of 218m and a relative height of approximately 110m, this castle retains remnants such as earthworks, baileys, and moats, conveying the appearance of a medieval castle.
Currently, the site is occupied by communication facilities and forest, so some preparation and consideration are necessary for a visit. However, the unspoiled, pristine landscape of this medieval mountain castle is a major attraction for castle enthusiasts.
Despite its relatively accessible location, approximately 2.4km from Iwama Station on the JR Joban Line, Izumi Castle remains a hidden gem. Visiting it in combination with other tourist spots such as Kasama Castle, surrounding castles, and Kasama Inari Shrine allows for a deeper understanding of the history and culture of Kasama City, Ibaraki Prefecture.
Many undeveloped medieval castles like Izumi Castle remain in the Kanto region. Visiting, documenting, and passing on these castles to future generations is a responsibility of us modern people. We encourage history lovers to visit Izumi Castle and experience the medieval history that breathes within its tranquil atmosphere.
