Japan's Island Geography and Seismic Activity

Japan consists of four principal islands — Honshu, Hokkaido, Kyushu, and Shikoku — together with the Ryukyu Islands stretching southwest toward Taiwan and thousands of smaller islands and islets. For decades, the official count stood at 6,852 islands, a figure established by a 1987 survey from the Japan Coast Guard. In February 2023, however, the Geospatial Information Authority of Japan (GSI) released a new count of 14,125 islands, more than double the earlier figure, after using modern digital elevation mapping techniques to identify islands of at least 100 meters in circumference that earlier, less precise cartographic methods had missed. The GSI stressed that the recount reflected improved measurement rather than any actual change in Japan's territory.