Japan slammed South Korea yesterday for trying to pass the buck on the issue of wartime forced labour, as frosty ties between the two US security allies chill even further in an increasingly acrimonious dispute.
Chief Cabinet Secretary Yoshihide Suga told a regular news briefing that Seoul's finger-pointing at Tokyo for "politicising" the issue was "extremely regrettable", and that the onus is on South Korea to resolve what ought to be its own domestic issues.
His remarks came one day after South Korean President Moon Jae-in called on Japan to express humility and stop politicising the issue.
Earlier this week, a South Korean court approved the seizure of Nippon Steel & Sumitomo Metal Corporation's assets in the country, after it refused to pay 100 million won (S$122,000) in compensation each to four South Korean plaintiffs in a seminal ruling last October.
Japan was forced to step in, Mr Suga said, because the ruling violates a 1965 internationally recognised agreement that forms the very basis of bilateral ties today.
Under the agreement, Tokyo paid US$500 million, or the equivalent of about US$4 billion (S$5.4 billion) in today's terms, for the "complete and final" resolution of colonial-era reparations. This is binding to South Korea's judiciary branch as well, Mr Suga added.
But while past South Korean administrations recognised that the deal includes individual claims, the courts have now ruled otherwise.
Seoul prosecutors, meanwhile, are grilling former chief justice Yang Sung-tae, 70, for allegedly pressuring justices to suspend rulings to curry favour with former president Park Geun-hye.
The precedent of the Nippon Steel ruling led to a November verdict against Mitsubishi Heavy, which was ordered to pay up to 150 million won each to 11 people.
Adding fuel to the fire was a ruling yesterday against Osaka-based shipbuilder Hitachi Zosen, which was ordered to pay 50 million won to a wartime labourer. Lawsuits involving about 70 Japanese companies are said to be pending.
Japanese Economy Minister Hiroshige Seko yesterday said these developments are detrimental to business sentiment of Japanese companies in South Korea.
On Wednesday, Tokyo requested formal bilateral talks, as allowed for under the 1965 agreement should the interpretation of terms come under dispute. This is the first time such talks have been sought, but as of yesterday, Seoul reportedly had not responded.
If this fails, Japan can take the case to the International Court of Justice, as it has said it will do as a matter of last resort.
Since the October verdict against Nippon Steel, the two countries have been in a row over the dissolution of a foundation set up by Seoul with Japanese funding to compensate former comfort women, and the lock-on of a fire-control radar by a South Korean warship on a Japanese patrol plane.
Japan's media yesterday accused Seoul of letting the crisis fester. Emotions are high in South Korea, which this year marks the 100th anniversary of the March 1 uprising against Japanese colonialism.
Emeritus professor Shinya Murase of Tokyo's Sophia University, who is a member of the United Nations International Law Commission, told The Straits Times: "The issue is quite clear: Korea's handling of the issue (including the Supreme Court and the government) is contrary to the 1965 agreement on the settlement of claims."
Senior fellow Tsuneo Watanabe at the Sasakawa Peace Foundation think-tank said that if Japan does not stand firm, "any kind of bilateral agreement with South Korea will not be effective in future as and when the government changes".
He said South Korean administrations tend to pull the history card whenever approval ratings fall, and that Mr Moon is "clearly facing a crucial political moment".