Visit Kyushu
The Official Kyushu Travel Guide

This jagged bed of rock stretches eight kilometers along the coast of Aoshima Island, just south of Miyazaki's city center. The bed of rock has straight ridges, which are the result of erosion, giving it the appearance of an old-fashioned washboard.

Aoshima Island is connected to the mainland by a pedestrian bridge and is home to beaches and a shrine. You can view the rock formations from the bridge as you approach the island. At low tide, rock pools form, containing crabs and other small sea creatures.