Japan renewed its claim to South Korea's easternmost islets of Dokdo in a revised guideline for school textbooks unveiled on Tuesday.
The textbook guideline, posted on Tokyo's e-government website for public view before the official announcement, will apply to elementary school textbooks from 2020 and to middle school books from 2021.
Currently, Japan is teaching its elementary and middle school students in social studies textbooks that Dokdo, called Takeshima in Japan, is its territory. But this is the first time that Tokyo specified the claim in the legally binding educational guideline.
The guideline, which is usually revised every 10 years, serves as a state-enforced standard for writing textbooks.
The move came in spite of strong protest from South Korea last month when it was reported that Japan's education ministry was pushing to revise the guideline to include its sovereignty claims to the islets.
Dokdo, which lies closer to South Korea in the East Sea, has long been a source of tension between the neighbors.
South Korea has kept a small police detachment on Dokdo since its liberation from Japan in 1945 and has made clear that Tokyo's claims are utterly groundless.
The revision came amid deepening diplomatic friction over a statue, symbolizing the victims of Japan's wartime sexual slavery of Korean women, recently erected in front of the Japanese consulate in South Korea's southern port city of Busan.
Tokyo demanded the immediate removal of the statue and called home its ambassador in protest last month. The ambassador has not come back to Seoul. (Yonhap)