Akizuki Castle, Japanese castle in Asakura, Japan

Akizuki is a fortified complex at the base of Mount Kosho, where stone walls, moats, and preserved gates mark its strategic position in a mountain basin. The grounds spread across several levels, with remnants of defensive structures still showing the original layout today.

The fortress arose in 1624 through Kuroda Nagaoki, the third son of the Fukuoka domain lord, who received 50,000 koku of land to establish the Akizuki domain. The Kuroda family managed the territory until the abolition of the feudal system in the 19th century, shaping the region permanently.

The shrine on the castle grounds is named Tayū Shrine (垂裕神社), dedicated to Kuroda Nagaoki, the castle's founder. Its gate is the former main gate (Kuromon) of Akizuki Castle, and the nagayamon gate that once served as the rear gate also stands on the grounds. Both gates are prefectural tangible cultural properties.

The grounds now house Akizuki Junior High School, so some areas remain off-limits during school hours. Paid parking sits nearby for visitors arriving by car.

The castle site now serves as the grounds of Akizuki Junior High School; its wooden school building, still in use by pupils, is regarded as a symbol of the castle town. The former rear gate, the Nagayamon, and the main gate, the Kuromon, were moved to stand as the gates of Shūyu Shrine.