It is also called Arioka Castle (有岡城 or 在岡城, Arioka-jō).Its ruins have been protected as a National Historic Site since 1979.

[3] At its height, the castle extended from 1.7 kilometers north-to-south by 0.8 kilometers east-to-west, and was an early example of a Sogamae (総構え) type of fortification in which the entire castle town forms part of the defenses by being completely encircled by moats and earthen ramparts, and with the arrangement of streets and townhouses planned as part of the defensive belt.

The structure was strong enough to withstand attacks by Oda Nobunaga's large army for a year.

The east side of the castle site was destroyed in 1891 due to railway construction, and most of Honmaru (inner bailey) has been lost.

Archaeological excavations were performed on the site from 1975, with remnants of moats, wells and stone walls uncovered.