The sea is only as blue as the sky permits. Even in the deep southern islands of the Nansei-Shoto, an overcast day can turn the sub-tropics into a mirror image of some of the more relentlessly dreary resort towns of my own country, England. One thinks of the ingloriously named Minehead, the estuary wilderness of Canvey Island, the pebble shore at Chesil Beach.

I was fortunate, however, to share the same sensations of light and color as the photographer Shomei Tomatsu, who, sailing past these islands en route to the nearby headland of northern Okinawa in the 1960s, was inspired to write of "a sea so blue that it looks as if it would turn your own skin blue if you put your hand in it."

Peering from the handrail of the Marix Line ferry as it docked beside the concrete pier on Yoron Island, I scoured the scene for any sign of transportation. After discovering that local buses omit the dock from their routes, I decided to call the Marina del Rei, where I was booked for the next three nights of my stay. At the first ring, someone tapped me on the shoulder. This turned out to be the owner herself, whose grandson, having better eyesight, had picked me out of the crowd. On request, I was dropped off at a scooter rental outlet in Chabana, the island's main town.