Japanese authorities have launched a research mission to find out why an uninhabited Japanese island used to identify territorial waters has disappeared.
Isan Bihanaki Takujima is located 500 meters from the coast of Sarovutsu village near the northern tip of Hokkaido, one of 158 uninhabited islands to clearly distinguish Japanese territorial waters.
Under international law, islands can be classified as such only if they can be seen above sea level even at high altitudes.
The sinking of the island to reduce the territorial waters of Japan, and classified the Geographical Information Authority spatial Japanese island on the map based on a maritime scheme was established in 1988.
"There is a possibility that the island has been eroded by wind and snow and has disappeared as a result," Coast Guard official Tomo Fuji told reporters.
The Coast Guard is also planning to investigate the area to ensure the safety of ships' navigation.