The Number of Japanese Islands Has Increased... Including Korean Territory 'Dokdo'

7,000 More Compared to 35 Years Ago
Included in Textbook White Paper Including Dokdo

Recently, Japan conducted a re-survey of its islands and confirmed that there are 7,000 more islands than previously known. It was also revealed that Dokdo, which is under Korean jurisdiction, was included in the count as a Japanese island.

Dokdo Panorama

On the 28th of last month, the Geospatial Information Authority of Japan (GSI) posted on its website the updated total number of islands nationwide based on the 2022 "Digital National Basic Map." The total number of islands in Japan was confirmed to be 14,125. This figure is more than twice the 6,852 islands surveyed by the Japan Coast Guard in 1987.

The GSI explained that the increase in the number of islands is likely due to advancements in surveying technology, which have enabled more accurate map drawing. In fact, at the time of the count 35 years ago, there was no technology to distinguish between small island clusters and large individual islands, resulting in thousands of islands being counted as one.

The GSI stated that they used computers to automatically count islands based on the digital national map and cross-referenced past aerial photographs and other data. Artificially reclaimed land was excluded from this count. Although the computer detected over 100,000 islands, only those with a perimeter of 100 meters or more were listed.

However, Dokdo, under Korean jurisdiction, was included in this count. The Nihon Keizai Shimbun reported that the new count will be used as the official standard when preparing textbooks and white papers published by various government ministries.

This re-survey was conducted following a statement by ruling party Liberal Democratic Party member Chiko Arimura in December 2021 at the National Diet, saying, "Accurately understanding the number of islands is an important administrative issue related to national interests."

Meanwhile, there is no international consensus on how to count islands. However, according to the United Nations Convention on the Law of the Sea, an island is defined as "a naturally formed area of land, surrounded by water, which remains above water at high tide."