Hashigui-iwa is the view most travellers remember from Kushimoto: a broken row of stone pillars stretching across the shallows toward Oshima Island. At low tide the rocks look almost walkable; at sunrise or after a storm they feel more like a myth than a geology lesson.
The site is easy to reach from central Kushimoto, which makes it the first stop even if you only have a few hours. Give it time rather than treating it as a roadside photo stop, because the mood changes quickly with tide, cloud, and light.