Built by the Asano clan in the Edo period, it was the center of Akō Domain in western Harima Province.

[1] Within the castle grounds is the Nagayamon gate to the residence of Ōishi Kuranosuke, the karō of the domain under Asano Naganori.

The house itself no longer exists, but its location has a separate National Historic Site designation.

However, after the area was awarded to Tokugawa Ieyasu's general and son-in-law Ikeda Terumasa after the Battle of Sekigahara, and a new castle was constructed.

Although it is now far from the coastline, at the time of its construction it was built on the seashore, and it was possible to sail from docks located in the castle.

Many of the buildings were pulled down, and portions of the stone walls were demolished to be used as a revetment when the Chikusa River flooded in 1892.

Subsequently, several buildings and structures of the inner area have been restored, including the Otemon main gate in 1955.