Blue Cave

Everything at Cape Maeda starts on top of the headland and finishes at the water below it, and before anyone kits up there is one thing to check: the cape's official site publishes the state of the sea that day and whether entry to the water is permitted. In bad weather it is not, and that call covers divers and swimmers alike. At low tide you can reach the cave on foot along the rock wall from the stairway; otherwise it is a swim from the entry, or a few minutes by boat from Maeganeku fishing port.

The cave is a tunnel cut into the cliff face and only half flooded, with four to six metres of air between the water and the ceiling and five to eight metres of water underneath. That is why one entrance serves snorkellers and divers alike: you can float in on the surface, and the light inside stays soft enough that no torch is needed above water. The blue is not light thrown on the walls. Sunlight enters the mouth, passes through clear water, reflects off the white limestone sand on the floor and comes back up through the surface inside the dark chamber. Morning, midday and evening each give a different shade of it.

Under water it is dimmer, and a light picks out Ryukyu sweepers and soldierfish schooling in the dark corners, with clownfish among the southern-Japan cast around the mouth. Visibility improves in winter, and whitetip reef sharks and spiny lobster are seen inside the cave then. The local name, Kumaya Gama, comes from the days when fishermen took their hand-rowed sabani in here to sit out a typhoon; the modern advice is the one the Japanese description gives, which is to be shown the place by someone who knows the ground.