Guida
The Kii Castle Ruins (Kii Jō Ato) is a Special Historic Site located in Kiyama Town, Saga Prefecture, known as one of the oldest authentic mountain castles in Japan. It is believed to have been constructed around the year 665 (the 4th year of the Tenchi era) to strengthen the defense of the Dazaifu region. The structure is characterized by its clever use of natural topography, featuring an extensive system of earthen and stone walls spanning approximately 4 km. Today, the site serves as a preserved museum of ancient fortification techniques, offering profound historical value to all visitors.
This site was constructed following the defeat in the Battle of Baekgang, necessitating a stronger defense system centered around Dazaifu. Due to its specific structural characteristics, it is referred to as a "Korean-style mountain castle," showcasing architectural influences from the Asian continent. The site also has a history of being reused as "Kiyama Castle" during the medieval period, serving as a strategic defense point from ancient to medieval times. It was designated as a National Historic Site in 1937 and became the first Special Historic Site in Saga Prefecture in 1954.
Within the castle grounds, you can observe earthen and stone walls built to follow the natural terrain. Particularly noteworthy are the "water gate remains," built to block valleys, and the traces of the castle gates, which demonstrate the advanced defensive technology of the era. Additionally, traces of approximately 40 buildings have been identified, with the "foundation stones" (礎石) still exposed. These are believed to have functioned as warehouses for weapons and food supplies. Near the western earthen walls, a large group of "great foundation stones" exists, providing clues to the massive scale of the structures that once stood there.
The Kii Castle Ruins is developed as a hiking course that utilizes the natural landscape, offering different views depending on the season. From the summit, you can enjoy a panoramic view of the surrounding area. In winter, the summit area is sometimes used for grass skiing. Visiting during the bright daylight hours is highly recommended, as it allows for a detailed observation of the earthen walls, stone walls, and foundation stones.
Visitors can enjoy hiking through historical ruins. The route from near the Kiyama Town Community Center toward the summit allows you to walk through the actual ancient fortification structure. By following the well-maintained paths, you can observe specific defensive features like the earthen embankments and water gates up close. The summit area is also a beautiful natural environment used for trekking and leisure.
The area around Kiyama Town is rich in historical sites and natural beauty. The castle ruins feature a well-maintained hiking course that allows you to experience a stroll integrated with the surrounding nature. The summit area also serves a dual function as a space for seasonal outdoor activities like grass skiing.