[1] Shōzui Castle is located on a loop of the former course of the Yoshino River, approximately five kilometers north from the center of Tokushima city.

Sumimoto mustered the support of the Miyoshi clan, who had once been the Awa Hosokawa's ancient enemies and how had now become their main retainers, and was able to defeat Sumiyuki.

Hosokawa Harumoto counterattacked in 1532, decisively defeating Takakuni, bout soon afterwards, he had a falling out with the Miyoshi clan which led to open warfare.

The weakened Miyoshi clan were driven back to Shikoku by the forces of Oda Nobunaga, where rent by internal squabbling, they were attacked by Chōsokabe Motochika from Tosa Province.

The original residence of the Hosokawa was in the northwest corner of the castle, at the site of the Buddhist temple of Chifuku-ji.

Portons of a water moat which once surrounded a 100 square meter compound remain, along with the remnants of a dry landscape garden.