The "sukui" is a traditional fishing weir. It is the stone walls assembled in a semi-circular shape at the seashore, and the fish trapped inside the walls are harvested at low tide. It is made with blocks of lava discharged from the Unzen Volcano.
In the early years of the Meiji era (1868-1912), there were more than 200 of sukui along the coast of Ariake Sea. One of them still remains at the Osakibana Cape. Students of local elementary schools carry out the annual cleanup activity here and have been making efforts for preserving the sukui.