According to a survey conducted by theJapan Coast Guard in 1987, the number of islands in Japan was 6,852. At that time, the survey only counted islands with coastlines of 100 meters or more that were shown on paper maps.On February 28, 2023, theGeospatial Information Authority of Japan announced that the number of islands had been updated to 14,125 through a recount using digital maps. Since there is no international standard for counting islands, only islands with a coastline of 100 meters or more were counted, as in the past. According to the GSI, advances in surveying technology and the detailed representation of topographic features through digital mapping contributed to this announcement.[4][1]
Hokkaido – the northernmost and second-largest main island, third most populous.
Honshu – the largest island, with the capitalTokyo and over 80% of the population. Honshu is connected to the other three main islands by bridges and tunnels.
Kyushu – the third-largest main island, second most populous and the nearest to the Asian mainland.
Shikoku – the smallest and least populous main island, located between Honshu and Kyushu.
Taiwan andPenghu (1895–1952) - part of the Empire of Japan until its defeat in 1945. Taken over by theRepublic of China in 1945 but no treaty of sovereignty transfer has been signed. All claims relinquished by Japan in theTreaty of San Francisco signed in 1951.
Karafuto (1905–1949) - the southern half of the island ofSakhalin, controlled by Japan after theRusso-Japanese War. Japan lost control of Karafuto after itsinvasion by the Soviet Union during World War II. Formally abolished as a legal entity by Japan in 1949. Japan in addition controlled the northern half of Sakhalin between 1920 and 1925, during and after theRussian Civil War.
