The winter vocabulary of the majority of Japan residents doesn't include the color turquoise. Or aquamarine, azure or the somewhat intellectually pompous "cerulean." This, however, is the palette I attempt to describe with my husband as we turn our tiny rental car onto the bridge leading to Kouri Island, a tiny speck just off the northern coast of Okinawa's Motobu Peninsula.

Sea foam, teal, cobalt ... we mull over more hues of blue as we travel the 2-kilometer bridge, the longest such structure in Okinawa. In a prefecture known for its stunning seascapes, the shifting color scheme in the small channel that separates Motobu's Yagaji Island from this tiny outpost of a few hundred souls recently became one of the most photographed and fawned over. Coming as we are from the gray concrete of Japan's capital, the starburst of blue is admittedly mesmerizing.

The bridge drops us straight onto the road that rings the tiny island and we turn left, heading up to the cliffs on the western side. Fields of sugarcane line the byway, their feathery stalks making it hard to see beyond the asphalt. Small breaks in the brush reveal clusters of homes and the occasional cafe. On the north side of the island, narrow lanes lead down to long stretches of pristine sand. Somewhere offshore, the wreck of the USS Emmons, a naval vessel sunk by kamikaze pilots during the waning months of World War II, lies hidden under the glassy surface.