Efforts to build forward-looking relations between Seoul and Tokyo have been held back by issues related to Japan’s 1910-45 colonization of the Korean Peninsula.

In a move set to further strain bilateral ties, a court here last week delivered a landmark ruling ordering Tokyo to make reparations to South Korean women forced into wartime sexual slavery for Japanese soldiers. The ruling comes amid rising tensions between the two countries over an ongoing legal process here to seize and liquidate South Korea-based assets of Japanese firms to compensate victims of forced labor during the colonial era.

Tokyo argues that the sexual slavery issue was settled by a 2015 deal with Seoul, while the forced labor issue has also been resolved by a 1965 treaty to normalize bilateral relations.

Soon after the ruling, Japan’s Foreign Ministry summoned South Korea’s Ambassador Nam Gwan-Pyo to file a protest and stressed that Tokyo could never accept the court’s decision.

Tokyo in particular noted the ruling was in violation of a principle of international law that stipulates a sovereign government cannot be subject to trial in another country.

In handing down the ruling, however, the Seoul Central District Court said the case filed by 12 of former sex slaves -- euphemistically called “comfort women” -- should be exempted from the principle as it involved a crime against humanity that violates internationally obligatory norms.

The latest court decision may prompt a series of other compensation lawsuits against the Japanese government, further straining Seoul-Tokyo ties already beset by issues stemming from the unfortunate history shared between them.

Japan imposed curbs on exports of high-tech materials to South Korea in 2019 in an apparent reprisal for the 2018 ruling by the Supreme Court here that ordered Japanese firms to compensate victims forced to work for them during colonial rule. If Seoul takes legal steps to enforce Friday’s ruling, Tokyo is certain to make a more serious and far-reaching response.

The ruling is expected to complicate Seoul’s recent efforts to mend ties with Tokyo by sending top government and ruling party officials for talks with Japanese Prime Minister Yoshihide Suga and others in Tokyo.

The move was seen as motivated to enlist Tokyo’s support for Seoul’s efforts to forge an environment for reengagement with Pyongyang particularly on the occasion of the Tokyo Olympics scheduled for later this year. It also came amid the need to prepare for the incoming US administration’s possible bid to bring its two key Asian allies closer together to cope with growing military threats from North Korea and an increasingly assertive China. US President-elect Joe Biden, who will be sworn in on Jan. 20, has pledged to strengthen solidarity with America’s democratic allies to enhance Washington’s interests and tackle a set of global challenges.

Seoul and Tokyo need to strive to contain tensions between them from further escalating, while continuing to seek fundamental measures to put the unfortunate history behind them.

Japan should make a more sincere atonement for and pay more heed to demands from the victims of sexual slavery and forced labor.

South Korean President Moon Jae-in’s administration is also urged to step up efforts to work out political and diplomatic solutions to prolonged disputes with Tokyo over historical issues.

It has backpedaled on the implementation of the 2015 deal that the predecessor Park Geun-hye government concluded with Tokyo to settle the comfort women issue on grounds that it did not properly reflect the opinions of the victims. Under the accord, Tokyo offered 1 billion yen ($9.6 million) to a foundation to support the victims and said that it “felt strongly” about its responsibility for the “issue involving the Japanese military that has left deep scars on the honor and dignity of many women.”

The Moon administration has also remained inactive on resolving the forced labor issue, saying only it should respect the judicial judgment.

Observers note repeated calls for compensation and apology seem to have further strengthened the position of Japan’s hawkish right-wing politicians, weakening its conscientious voices.

Now is the time the Moon government should come forward to put forth solutions to build forward-looking ties no longer tethered to historical disputes.