Ryo-oka Castle

Overview & Attractions

Ryo-oka Castle is a historic Japanese castle site located in Taguchi, Saku City, Nagano Prefecture. It served as the administrative center for the Ryo-oka Domain (Tanoguchi Domain) during the late Edo period. The site is famous for being one of only two pentagram-shaped star fortresses in Japan. Due to its extremely rare shape, it is often referred to as "Ryo-oka Goryokaku" (alongside the famous Goryokaku in Hokkaido) or "Kikyo Castle," named after the bellflower shape. Today, it is a designated National Historic Site where visitors can observe the architectural design principles of that era.

History & Cultural Background

The castle was constructed during the late Edo period. While it was the base for the R-yo-oka Domain, it was officially known as the "Tanoguchi Jinya" because the status of its lord was not officially elevated to a full castle. The history following its abandonment is equally fascinating. Much of the castle grounds were repurposed for agriculture, and the former residence (Odaidokoro) was once used as a warehouse for farming tools. From 1875, the building even served as a local elementary school. This transition from a military stronghold to an agricultural and educational center reflects the local history. Interestingly, parts of the original castle buildings were dismantled and moved to nearby temples, shrines, and private homes, allowing the castle's architectural legacy to blend seamlessly into the local community.

Main Highlights

The site preserves bastion-style stone walls, water moats, and the remains of the Odaidokoro. These structures are invaluable resources for understanding advanced fortification techniques of the time. To the northwest, visitors can observe the "Masugata" (gatehouse) remains, showcasing the meticulous defensive design. Because the site once functioned as a school, there are also historical traces related to its time as an educational facility. For a breathtaking view, the area around the former Taguchi Castle ruins to the north offers a panoramic perspective of the entire star-shaped layout. If you wish to capture the unique shape from above via drone, prior permission from the Saku City Hall is required.

Seasonal Recommendations

Ryo-oka Castle is an open-air site that can be explored freely regardless of the season. Walking through the historical remains is a peaceful experience, especially during quieter hours when the atmosphere of the ancient fortress is most palpable. The observation area to the north provides a wonderful vantage point to see the castle's structure from a distance. While the surrounding landscape changes with the seasons, the historical charm of the ruins remains constant throughout the year.

Experiences & Activities

There are several facilities nearby to deepen your understanding of the site. The "Saku City History Village Aino-kan," located near the Otemon gate, features valuable exhibits regarding Ryo-oka Castle. Additionally, if you make a prior reservation, you can tour the interior of the Odaidokoro to see the intricate details of the historical architecture and former living spaces. For those interested in local art, the "Kuramura Gozo Memorial Museum" nearby showcases the works of the famous local sculptor, providing a deeper connection to the region's culture.

Surrounding Area

The area surrounding the castle is rich with historical connections. For example, the former main hall (Daihiro) was moved to Jisho-ji Temple in Naruse, Saku City. The eastern gate was relocated to become the gate of Naritayama Yakushi-ji Temple, and other walls and gates were integrated into private residences along the path to Shinmai Sansha Shrine. These architectural fragments scattered throughout the local temples and homes create a unique cultural landscape. To the north, a path leads up approximately 160m to the site of the medieval Taguchi Castle.

Things to Note

When visiting the castle ruins, please keep the following in mind:

• Payment: While the general site is free to explore, please carry cash if you wish to visit nearby facilities or participate in specific-interest experiences.
• Language Support: Most signage is in Japanese. English support is limited.
• Reservations: A prior reservation is required if you wish to tour the interior of the Odaidokoro.
• Clothing: The terrain includes unpaved paths and uneven surfaces; comfortable walking shoes are highly recommended.
• Photography: Photography is allowed, but using a drone requires permission from the Saku City Hall.
• Accessibility: Due to the uneven terrain, stone walls, and moats, the site is not easily accessible for wheelchairs.
• Etiquette: Please respect the historical site and maintain a quiet atmosphere during your visit.