Kasai

Kasai occupies the western part of the Tokachi plain, between the Tokachi and Satsunai rivers and the Hidaka Mountains. Before Japanese settlement expanded across the plain, Ainu communities lived in villages along the rivers and used the surrounding forests and waterways. The rivers descend from the mountains across a broad inland basin before reaching the Pacific. Place names in the region preserve traces of its Ainu inhabitants and their relationship with the land.