The Minato Ruins are located in the Nakasho district on the left bank of the lower Sano River. The ruins are known because the settlements were involved in salt production on Osaka Bay from the late Yayoi period (300 BC-300 AD) to the early Kofun period (about 300-538 AD). In the Nara period (710-794), the settlements were main coastal bases, with residences and warehouses built with dug-standing pillars.

Markets were also established in association with the development of Kumano Kaido (a pilgrimage road) in medieval times according to the Masamoto-ko Tabihikitsuke and other sources. This eboshi (headgear worn by court nobles) was found in the remains of a workshop in a settlement established around the Kamakura period (1185-1333). Made of black lacquered fabric, it has remained largely intact and was already squashed when it was discovered on a floor created while excavating the grounds within the ruins. It is considered that the eboshi belonged to an adult male and that it was probably worn by a craftsman.

The excavation also found the remains of buildings with dug-standing pillars and dokobo (hole-shaped graves). They demonstrate that people working in a variety of occupations, including producers of earthenware, roof tiles, agricultural tools and articles for daily life such as combs, as well as blacksmiths, were living in the shoen. A conservation treatment has been applied to the eboshi, which is now stored in Lake Alster Plaza Kawasaki History Museum Izumisano.