Maruoka Castle, located in Kasumi, Maruoka-chō, Sakai City, Fukui Prefecture, is a historic hirayama-style (hilltop) castle, also known by the nickname “Kasumijō” (“Mist Castle”). Built atop an isolated hill on the eastern edge of the Fukui Plain, it holds a naturally defensible position. During the Edo period, Maruoka Castle served as the administrative center of the Maruoka Domain, functioning as both its political and military hub. Its existing tenshu (main keep) is one of only twelve surviving original tenshu in Japan and is designated an Important Cultural Property—the only existing tenshu in the Hokuriku region.

The castle was first built during the Azuchi–Momoyama period, believed to have been constructed in 1576 (Tenshō 4) by Shibata Katsutoyo under orders from his uncle, Shibata Katsuie. Since then, its lords changed several times, passing through the hands of the Aoyama, Honda, and Ario clans, reflecting shifts in regional power from the late Sengoku period to the Edo period. In the early modern era, the castle’s lower slopes were expanded, and a pentagonal inner moat was constructed, combining defensive functionality with aesthetic appeal.

The nickname “Kasumijō” comes from an old legend: during a fierce battle, when the castle was on the verge of falling, a giant serpent appeared and released a thick mist, concealing the entire fortress from the enemy, who then withdrew. This tale added a sense of mystery to the castle and made “mist” its enduring symbol.

The present tenshu is an independent watchtower-style structure with two main floors and a third hidden story, featuring a large irimoya-style roof at the lower level and a small watchtower with a surrounding balcony on top. The stone base is built using the nozura-zumi technique, giving it a rough and solid appearance. The original roof was made of wooden shingles and decorated with lacquered and gold-leafed shachihoko (ornamental tiger-headed carp). Later, it was replaced with tiles made from Shakudani stone, a specialty of Echizen Province, and in modern restorations, with stone tiles from Takigahara in Komatsu City, Ishikawa Prefecture. Inside, the wooden staircases are extremely steep and narrow, so ropes have been added to assist visitors in climbing.

The tenshu was completely destroyed in the 1948 (Shōwa 23) Fukui earthquake but was rebuilt in 1955 (Shōwa 30) to its original design, using over 70% of the original materials, thus preserving much of its historical authenticity. However, during the reconstruction, the top-floor windows were changed from sliding doors to shito-mido (hanging lattice shutters).

Around the castle, some original structures and relocated buildings remain, such as castle gates now found at Kōzenji Temple in Komatsu City, Ishikawa Prefecture, and Renshōji Temple in Awara City, Fukui Prefecture, as well as the “Unknown Gate” preserved in a private residence. Stone walls, earthen walls, and other features still display the castle’s former grandeur. Since 2015, Sakai City has established the “Maruoka Castle National Treasure Promotion Office” to pursue National Treasure designation and plans to restore the inner moat, several gates, turrets, and the ninomaru palace, aiming to recreate the complete Edo-period castle layout.

Fukui Prefecture Tourist attraction list

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Ichijodani Castle

Maruoka Castle