Nagasaki and Kagoshima prefectures in south-western Japan had 1,479 and 1,256 islands respectively. - ST FILE
TOKYO (The Straits Times/Asia News Network): The number of listed Japanese islands is expected to more than double from 6,852 to 14,125, according to Japanese media reports.
This is after the government re-counted them for the first time in 35 years, a source familiar with the matter told Kyodo News on Monday (Feb 13).
The jump is due to improved accuracy with the digitalisation of maps.
However, it is unlikely to change the size of Japan’s territory or its territorial waters.
The number of islands could change though, as the Geospatial Information Authority of Japan, or GSI, is making final adjustments, the source said.
The Japanese government is expected to release the new figure as early as March.
The re-count happened due to criticism that the existing data was old and the true figure could be dramatically different.
The updated figure could affect entries in educational and other materials.
The government has been using the figure released in 1987 by the Japan Coast Guard.
At the time, the coast guard listed, by hand, islands with a circumference of 100m or greater that were shown on a map of Japan.
Islands in lakes or river sandbanks were not included in the total.
In the latest survey, the government counted islands automatically using a computer, based on GSI’s electronic land map in 2022.
It cross-referenced the map with past aerial photographs and other data in order to exclude artificially reclaimed land.
While the computer detected more than 100,000 islands, only those with circumferences of 100m or greater were selected for the official list.
The total size of national territory is calculated using the same digital map irrespective of listed islands.
The extent of territorial waters will not be affected, as remote Japanese islands are subject to a separate survey.
Nagasaki and Kagoshima prefectures in south-western Japan had 1,479 and 1,256 islands respectively, while 1,473 were listed in Hokkaido, northern Japan.
The re-count came after a ruling Liberal Democratic Party lawmaker told a parliamentary session in December 2021 that “an accurate understanding of the number of islands is an important administrative matter that is related to the national interest”.
Islands in the survey are defined in line with the United Nations Convention on the Law of the Sea.
It states that an island is a “naturally formed area of land, surrounded by water, which is above water at high tide”.
