Just a week after hailing a visit to Japan by Prime Minister Yoon Suk Yeol as a "big success," the South Korean government has lodged an official protest with Tokyo over new elementary school textbooks it claims distort history.
With China also weighing in, days before an expected trip there by Japanese Foreign Minister Yoshimasa Hayashi, the latest spat is an example of how historical and territorial disputes continue to hamper Tokyo's efforts to improve ties with its neighbours.
"It is common for Japan to play with words when authorizing textbooks to obscure historical facts, understate and evade its historical responsibility, and thereby deny and misrepresent its history of aggression," Chinese foreign ministry spokeswoman Mao Ning said Wednesday, adding Beijing had also lodged a formal complaint.
The day before, Seoul summoned Japan's deputy ambassador to express "deep regret" over the issue, citing controversial claims about the disputed Dokdo Islands and the use of forced labour during World War II in the new materials.
Japan's education authorities recently approved 149 textbooks from various publishers for use from next year nationwide. While the text in these materials is not identical, South Korean media quickly seized on passages seen as diminishing wartime atrocities, such as the forced conscription of Koreans into the Imperial Japanese Army.
"For those who were forced to serve in Japan's military during World War II, a current textbook says Korean men were conscripted as soldiers," the Yonhap news agency reported "But a new version, endorsed by the ministry, describes them as 'having participated in' the military. Another textbook dropped the _expression_ 'conscription' itself."
Other materials also state Japanese claims to the Liancourt Rocks, which lie between the Korean Peninsula and Japan and are controlled by Seoul. The Korean name for the territory is Dokdo, while Japan uses the name Takeshima.
South Korea's foreign ministry said the textbooks contain "unreasonable claims about Dokdo, which is clearly our own territory historically, geographically, and under international law."
In response, Japan's deputy ambassador Naoki Kumagai said the islands were "an inherent part of Japanese territory, both historically and in terms of international law," according to NHK, a Japanese public broadcaster. "He also dismissed South Korea's claims on the wartime labor issue."
Beijing also expressed anger over passages describing Japanese claims to the Senkaku Islands, known as the Diaoyus in China, a disputed territory in the East China Sea administered by Japan.
While the textbook issue has received little attention in Japan, it dominated South Korean media this week, coming after President Yoon controversially agreed to use domestic funds to settle a forced labour dispute dating back to Japanese colonial rule.
Two Japanese companies — Nippon Steel and Mitsubishi Heavy Industries — were ordered by a South Korean court in 2018 to pay reparations to conscripted labourers. Tokyo insists all wartime compensation were settled under a 1965 treaty, and hit Seoul with export controls on key semiconductor materials.
The issue severely damaged relations between the two sides, even as Washington was pushing for greater economic and security co-operation in the face of threats from China and North Korea. Announcing the deal earlier this month, Mr. Yoon said it was a step towards "future-oriented co-operation between South Korea and Japan" that would "preserve freedom, peace and prosperity not only for the two countries, but also for the entire world."
He followed up with a trip to Tokyo, where he met Japanese Prime Minister Fumio Kishida, which both sides described as a major success and step forward in relations.
The textbook dispute could hamper this, ramping up pressure on Mr. Yoon to take a tougher line once again. In an editorial Wednesday, the liberal daily Hankyoreh accused the president of having waved a "white flag" only for this to "backfire immediately."
One solution could come from co-operation between Japanese and Korean historians, said Nam Sang-gu, a researcher at the Northeast Asian History Foundation.
"For Korea and Japan's future co-operation, the two countries need to better understand each other," he told a seminar in Seoul this week. "In that regard, textbooks play a crucial role."
So far, there is no sign the issue is going away. Opposition lawmakers on Thursday proposed a parliamentary resolution warning "the Japanese government's distorted perception of history could significantly hurt trust between South Korea and Japan," and calling for Tokyo to apologize.
On the same day, Seoul ruled out the resumption of seafood imports from Fukushima, the Japanese prefecture that was the site of a nuclear plant meltdown in 2011.
Tokyo has been facing pressure from its neighbours over a decision — supported by the International Atomic Energy Agency — to release more than 1 million tonnes of "treated" water from the disaster zone into the ocean later this year. Some in Japan had hoped improved ties with South Korea would see Seoul drop its objections to the plan, which has been repeatedly denounced by both China and Russia.