Japan’s colonial rule over the Korean Peninsula ended more than seven decades ago yet that legacy still roils everyday politics on both sides of the strait. South Korea and Japan, major trading partners and both U.S. military allies, have been at loggerheads over what constitutes proper contrition and compensation for two groups of Koreans: those conscripted to work in factories and mines that supplied Japan’s imperial war machine, and those euphemistically called “comfort women” who were forced to work in military brothels. Japan contends all claims were settled under a 1965 bilateral treaty and a fund set up in 2015. Seoul argues Japan hasn’t atoned enough. Some of Japan’s largest companies and the emperor himself have been dragged into the fray.

1. What are the roots of the forced labor dispute?

Hundreds of thousands of Koreans were conscripted during the 1910-1945 colonial period to work, often in brutal conditions, at dozens of Japanese companies. At the time of the 1965 treaty, which established diplomatic ties between the two countries, Japan paid the equivalent of $300 million -- $2.4 billion in today’s money -- and extended $200 million in low-interest loans. The treaty said all claims are “settled completely and finally.” The then-struggling South Korea invested that money in industries that eventually helped turn it into an economic powerhouse. However, South Korean court rulings since late 2018 said the victims were not compensated for their emotional pain and suffering.

2. What is the fallout for the companies?

South Korea’s Supreme Court ruled in 2018 against two of Japan’s largest companies: Mitsubishi Heavy Industries Ltd. was ordered to pay as much as $134,000 to each of 10 claimants, while Nippon Steel & Sumitomo Metal Corp. was ordered to pay $88,000 each to four plaintiffs. A South Korean court then ordered the seizure of shares valued at about $356,000 that Nippon Steel has in a joint venture with South Korean steelmaker Posco, a move Tokyo calls unlawful and is trying to block.

3. What has Japan done to push back?

Japan has invoked a part of the 1965 treaty that calls for arbitration for disputes that can’t be settled by normal diplomatic means. It rejected a South Korean proposal for a joint compensation fund to resolve the forced-labor dispute, seeing it as a breach of international law. The Japanese government in July moved to restrict exports of materials vital to South Korean manufacturers of semiconductors and computer displays. Prime Minister Shinzo Abe denied Korean assertions that the checks were a form of retaliation. The move contributed to declines in shares of Korean companies including Samsung Electronics Co. Ltd.

4. Are other companies affected?

There are more than a dozen such cases pending in South Korea involving about 70 companies, according to the Japanese Ministry of Foreign Affairs. An estimated 725,000 Korean workers were sent to mainland Japan, Sakhalin and the southern Pacific islands to work in the mining, construction, and shipbuilding industries, according to a Stanford University research paper. Most of the former laborers have died, but some of their family members have sought legal standing to sue.

5. What about the ‘comfort women’ controversy?

That’s also flaring. Historians say anywhere from 50,000 to 200,000 women -- many of them Korean -- were forced into service in Japan’s military brothels. There are fewer than two dozen known survivors in South Korea. In 2015, Japan and South Korea announced a “final and irreversible” agreement that came with a personal apology to the women from Prime Minister Shinzo Abe as well as about $8 million for a compensation fund. But many South Koreans opposed the deal, which was signed without consulting the victims, some of whom refused the money in protest. Under President Moon Jae-in, who took office in 2017, South Korea said it would shut down the fund, angering Tokyo. Then South Korea’s National Assembly Speaker Moon Hee-sang said in a Feb. 7 interview with Bloomberg News that Japan’s Emperor Akihito -- whom the speaker called “the son of the main culprit of war crimes” -- should hold hands with the women and personally apologize to them to end the dispute. Japan demanded an apology and retraction, while Akihito abdicated at the end of April.