10.Ainu Culture
There were significant changes to lifestyles in the Satsumon Culture from the 13th century onward. Flat level houses came to replace pit-dwellings, and iron pots obtained through trade came to be used in place of earthenware. In archeology, this era is the border of what is called the "Ainu Culture". The Ainu Culture which has been handed down to the modern day developed over the course several centuries from this era.
Clear evidence of ruins, such as pit-dwellings and pottery were no longer in use during this period, so very few ruins from this period have been discovered. However, ruins of "chashi"; which served as both strongholds and places for gatherings and ceremonies; and "okuriba"; where ceremonies were held to send the divine spirits of animals, tools, and other items to the land of the gods; and other ruins have been found. In addition, numerous wooden objects from this period have been found at the Tokoro River Estuary site, preserved and protected from rotting by underground water.