Why Japan and South Korea are fighting over this messaging app

Line, one of the most popular messaging apps used in Asia, is causing tension between Japan and South Korea, two countries that have been trying to improve their relationship. The app, which lets people send messages and use cute stickers, is now at the centre of a dispute that could affect how well these two important US allies work together.
Line was created by Naver, a South Korean company, but became very popular in Japan after the strongest earthquake hit the country in 2011 leaving phone lines to be completely unserviceable.
Years later, in 2019, Naver and SoftBank, a Japanese company, agreed to run Line together. The partnership, code-named "Gaia," was initially seen as a symbol of cooperation amid diplomatic strains.
But now, Japan wants Naver to sell some of its share in Line, as the New York Times report. Following a security breach in November last year, Japan's communications ministry issued a statement widely interpreted as a directive for Naver to reduce its stake in the joint venture, and the move has sparked outrage in South Korea.
"For the Japanese government to now demand Naver's exit, after all the hard work and investment, seems at odds with the principles of a civilised nation," stated an editorial in the Korea Economic Daily, as cited in the Times' report.
The Times reports that this fight over Line could hurt the improving relationship between Japan and South Korea. The two countries have had problems in the past because Japan ruled Korea many years ago.
The dispute comes at a sensitive time for Japan-South Korea relations. Maiko Takeuchi, regional managing director at CCSI, told the New York Times, "As we've seen many times in the past, relations between Japan and Korea shift, and smaller points of tension — whether they be wartime or modern — can quickly escalate to impact defence and diplomacy more broadly."
In South Korea, opposition parties have criticised President Yoon Suk Yeol for his conciliatory approach towards Japan. Cho Kuk, an ally of the former president, called Yoon's policies "humiliating."
Despite the controversy, both governments appear determined to prevent the issue from escalating. In late May, Japanese Prime Minister Fumio Kishida and President Yoon agreed that the dispute should not interfere with diplomatic relations.
Yul Sohn, president of the East Asia Institute in Seoul, told the New York Times that Japan's handling of the Line ownership issue could significantly impact the broader trajectory of Japanese-Korean relations."We are in a phase of recovering relations, but both parties are highly aware of what has happened in the past," Sohn said. "Even with a stronger foundation built, there are still cracks that need to be reckoned with."