TOKYO — South Korea's president has been promoting the Winter Olympics in Pyeong­Chang as the "peace Games," a way to bring North Korea into the international sports community for at least a few weeks and lessen the tensions on the peninsula.

But South Korean conciliation is proving harder with another neighbor: Japan. 

The precarious relationship between the United States' two most important security allies in Asia is currently in a low phase, brought down by a long-simmering dispute over history and complicated by differences over how to deal with North Korea.

"This is and always has been one of the most serious problems for U.S. policy in northeast Asia," said Daniel Sneider, an East Asia specialist at Stanford University. "We've been trying to push our allies together since the Korean War, and we've made only incremental progress over almost 70 years."

A delegation of North Korean officials and ice hockey players crossed the heavily guarded border into South Korea on Jan. 25. (Reuters)

Progressive South Korean President Moon Jae-in will meet with his conservative Japanese counterpart, Prime Minister Shinzo Abe, for talks at the Winter Olympics site on Feb. 9, the day of the Opening Ceremonies. 

Until last week, it wasn't even clear that Abe would attend. But the Trump administration intervened to ask him to go — not least because Vice President Pence will be traveling from Tokyo to Pyeong­Chang for the Opening Ceremonies. The White House "strongly urged" Abe to attend the ceremonies, a senior Japanese government official told the conservative Sankei Shimbun newspaper.

Together, Abe and Pence will be able to send "a strong message to South Korea" not to be too conciliatory toward North Korea and also to abide by their bilateral agreements, the paper reported.

This has sparked talk in Tokyo that Abe and Pence are going to PyeongChang to "gang up" on Moon, who favors closer relations with North Korea as a way to bring Kim Jong Un's regime in from the cold. Despite his efforts to include North Korea in the Olympics, Moon has publicly said he supports the "maximum pressure" approach espoused by the Trump and Abe administrations.

The trip to PyeongChang is aimed at making sure Moon sticks to that vow, said Kiichi Fujiwara, professor of international relations at the University of Tokyo.

"If we don't engage the Moon administration, they might get too far ahead of the U.S. and Japan on North Korea, and that would not be beneficial for Tokyo or Washington," he said. "So we should put aside our differences and present a united face."

Still, a slew of ruling Liberal Democratic Party lawmakers have criticized Abe's decision to go to PyeongChang — not because of the North Korean issue, but because of South Korea's behavior.

"He absolutely should not go," Takashi Nagao, an LDP representative in the lower house, wrote on Twitter, saying that Abe is just helping Moon boost his popularity by stoking anti-Japanese sentiment in South Korea.

This relates to Moon's criticism of a 2015 deal, which was supposed to be "final and irreversible," on sexual slavery during World War II.

"Even if there's some agreement to be reached in South Korea, we've seen over and over again that they don't stick to their agreements," Nagao said, echoing the sentiments of many in Japan.

But issues relating to Japan's occupation of the Korean Peninsula during the first half of the 20th century continue to plague relations between Tokyo and Seoul.

Historians say as many as 200,000 women in occupied countries were coerced by the Japanese Imperial Army to work as sex slaves, euphemistically known as "comfort women."

The Japanese government has issued repeated statements expressing remorse for the practice and set up a fund in the 1990s to help the women. But some Japanese right-wing politicians and academics have continued to insist that the women were prostitutes or that the number of sex slaves was much lower.

This has angered South Koreans, who view these critics as the equivalent of Holocaust deniers.

The issue has festered for years, often consuming meetings with the United States and even overshadowing discussions on the North Korean threat.

But the two countries seemed to reach a breakthrough at the end of 2015, when Abe expressed "his most sincere apologies" and Japan put $8.3 million into a new fund to help the surviving women.

When the deal was reached, there were still 46 comfort women in South Korea. Today, there are only 31 still alive. 

Moon, who became president last year, this month called the deal "seriously flawed" but said he would not seek to revise it. But he froze the money given by the Japanese government and said the South Korean government would provide the funds instead — essentially gutting the deal.

"We know that this has more to do with South Korean domestic politics than with anything else," said Narushige Michishita, a Korea expert at the National Graduate Institute for Policy Studies in Tokyo. "South Korea is using anti-Japanese sentiment for domestic political purposes, and they just can't stop doing this. There's no way for us to respond." 

Meanwhile, Japan has been angered that South Korean civil society groups have put up more statues to the comfort women, including one outside the Japanese Consulate in Busan, South Korea, and another in San Francisco. 

And so these old wounds have been reopened. 

"It's deja vu," said one senior Japanese government official working on the issue. When asked how frustrated he was, he held his hand above his head. 

"In 2015, we got lots of criticism in Japan from nationalists and lawmakers who said: Do you really believe that South Korea will abide by this agreement? Are you so silly once again agreeing to this and using our taxpayer money?" the official said, speaking on the condition of anonymity to talk frankly on the topic.

Announcing his decision to go to PyeongChang, Abe said he would use the meeting with Moon to "clearly state Japan's stance" on sticking to the 2015 deal. He also said he would tell Moon "of the need for Japan, South Korea and the United States to work together and maintain the maximum level of pressure to deal with the threat from North Korea."

Indeed, the ongoing dispute has serious implications for security in the region.

"We cannot fulfill our treaty obligations to defend South Korea without the cooperation of Japan," said Sneider of Stanford. "The entire structure of U.S. Forces Japan is to be available for the defense of the Korean Peninsula." 

The U.S. military has about 50,000 troops in Japan and 28,000 in South Korea, forward-deployed to be able to respond quickly to any provocation from North Korea. 

But there is little cooperation between the Japanese and South Korean militaries. Indeed, amid talk of a possible war on the peninsula, Japanese officials, with American encouragement, have been seeking to work out an evacuation plan for the 60,000 Japanese nationals living in South Korea.

Tokyo and Washington want to be able to send ships from Japan's Maritime Self-Defense Force, as its quasi-navy is known, to South Korean ports to collect them if conflict breaks out.

But South Korea's government is flatly refusing to discuss the idea, according to people involved in the effort. Even seven decades after liberation, the wounds remain fresh.