The main bailey was protected by a system of wet moats, earthenworks and eight yagura watchtowers; however, the castle made very little use of stone walls, which were not common in Hitachi Province, the previous homeland of the Satake clan.

The castle also never had an imposing main keep, possibly to prevent attracting unwelcome suspicion from the Tokugawa shogunate.

Satake Yoshinobu, was reassigned to Dewa Province from the clan's ancestral territories by Tokugawa Ieyasu in 1602, and arrived at the site of the Minato Castle in Tsuchizaki on September 17 of the same year.

Subsequently, most of its moats were filled in to widen city streets, and most of its minor structures were pulled down for scrap.

On July 21, 1880 a fire broke out in the abandoned main bailey, and destroyed it and most of the remaining structures.

The Akita city government planted it with 1170 sakura trees in 1892 and built a Shinto shrine on the site of the Main Bailey.

In 1984, the Satake clan donated the remaining 14.6 hectares of the former castle site to Akita City.