The Education Ministry also issued its own condemnation, expressing “deep disappointment and regret” over the decision and calling for a “fundamental rectification.”

Of the 35 social science schoolbooks newly certified by Japan’s Education Ministry, 27, or more than 77 percent, carry the sovereignty claim. By subject, 11 of 17 history books include it, up about 6.8 percent from 11 of 19 in the last round of the quadrennial deliberation in 2012.

The texts have also toughened their tone. The most popular geology book, authored by Daiichi Gakushusha, now states the Dokdo Islets are Japan’s territory though currently “occupied” by Korea, altering its previous description saying “there is a dominium issue with Korea.”

The Japanese ministry had also taken issue with relatively moderate accounts in a social studies book by Shimizu Shoin for being “incomprehensible for students,” prompting the publisher to change them to stipulate Seoul’s “illegal occupation” of the islets and Tokyo’s efforts to resolve the issue, such as through litigation at the International Court of Justice.

The previous Japanese history book from publisher Tokyo Shoseki only marked the Dokdo Islets on a map, whereas its new edition maintains that the islets were “incorporated into (Japan’s) Shimane Prefecture in 1905.”

The reinforced claims are in line with an amendment of authorization standards in January 2014, which called for basing historical statements on government-wide unified opinions and top court rulings, and stipulating that no “common account” exists on some modern history issues.

In the revised teaching guidelines for middle and high school students, the ministry specifically recommended that history, social studies and geography books state the Dokdo Islets are Japan’s “indigenous territory” and “illegally occupied by Korea.”

The latest deliberation coincides with Tokyo’s ongoing push to step up its territorial claim in primary and secondary education handbooks following its examinations on elementary and middle school books in 2014 and 2015, respectively.

On Japan’s sexual enslavement of Korean women and other nationals during World War II, 11 out of 17 approved books on history, two of 10 on modern society, and both of two on politics and economy address the issue.

But most of them retained the existing portrayals, though a few appeared to have sought to water down the forced nature of the women’s conscription, saying they were “sent,” instead of “taken,” to battlefronts, or omitting the role of the Japanese military as the main mobilizer.

All of the workbooks, however, failed to reflect the hard-won agreement on the “comfort women” issue reached at the end of last year between the two countries, because their certification applications were received in the first half of 2015.

The latest textbook claims are set to rekindle territorial spats that have for decades vexed the bilateral relationship, dampening Seoul’s efforts to reconcile with its old foe especially following the sex slavery settlement.

Tokyo has claimed sovereignty over the Dokdo Islets via schoolbooks, diplomatic and defense papers and other methods. Many Koreans couple the assertion and recurrent distortion of historical facts with hawkish Japanese Prime Minister Shinzo Abe’s revisionist drive.

At the height of the Russo-Japanese war in 1905, Tokyo illicitly annexed the windswept outcrops to install communication and surveillance devices and collect intelligence on Russian naval movements. Japan returned the islets to Korea after winning the war, but then soon pushed to occupy the entire peninsula.

“This announcement in effect represents the ministry’s final touch on its efforts to insert the Dokdo claim into compulsory education textbooks,” said Hong Seong-keun, head of the Dokdo Institute at the Northeast Asian History Foundation, during a seminar in Seoul later in the day.

“Yet not only is it extremely contradictory and distorted, the statements like ‘illegal occupation’ also run counter to Japan’s Basic Act on Education that calls for nurturing an attitude that respects other countries and contributes to peace and the development of the international community.”

By Shin Hyon-hee (heeshin@heraldcorp.com)