China’s artificial islands are fuelling a new struggle for control of Asia’s oceans, but while the regional superpower dredges military bases out of the ocean, Japan is growing an island in a bathtub.

The island is called Okinotorishima, or “distant bird island”; a remote, storm-wracked coral atoll in the Philippine Sea, where two small outcrops protrude at high tide. Japan regards the atoll as its southernmost point; China says it is no island, merely a rock.

For millennia, as the land beneath it sunk, layers of coral grew on top and kept the atoll’s head above water. But now Okinotorishima is dying. Climate change is raising the sea level and killing the coral. Typhoons bite at what remains.