The Japan-Korea relationship, already strained by the ‘comfort women’ controversy, faces new challenges after a Korean court ruled in favor of workers coerced to work for Nippon Steel during Japan’s 35-year occupation of Korea.

Japan resists further demands for compensation or new apologies related to its colonialism and war in Asia. It views the 1965 Treaty on Basic Relations between Japan and the Republic of Korea as having settled all controversies. But controversies continue to spring back up time and time again.

In 2015, Japan arrived at agreement with Korea on a plan to compensate Korea and its few remaining ‘comfort women’ with 1 billion yen (US$8 million) in exchange for “permanently” settling the issue. But after the Korean government refused to remove statues of ‘comfort women’ set up outside the Japanese diplomatic offices in Seoul and Busan, Japan threatened to withhold the money.

Korea’s new president Moon Jae-in threatened to try to renegotiate the ‘comfort women’ agreement, as he (and a majority of Koreans) opposed it. He felt it did not account for the wishes of the living former sex slaves and that Japan hadn’t apologizes forcefully enough. Japan, for its part, feels that Korea is always moving the goalposts.

Earlier in October, Japan did not participate in an international naval review held in Korea after Korea demanded that Japan’s navy remove its ‘Rising Sun’ flag. Japan had participated in fleet reviews before with that flag–the same flag it flew during World War II–but Korea apparently raised the issue strenuously this time because anti-Japan sentiment has been running high in recent years.

The ruling by Korea’s Supreme Court came 13 years after the case was first filed in Korean courts. The claimants, who were forced to work in the Japanese steel industry and had compensation withheld, originally filed in Japan, but their case was dismissed by Japanese courts in 1997 on the grounds that the 1965 treaty addressed compensation.

The treaty’s terms on individual compensation were limited, causing it to be unpopular in Korea, but it did call for Japan to provide $800 million to Korea in economic development. Japan provided that much and much more in additional investment and aid. Japan’s aid and investment was important, but not sufficient, for Korea’s development during the 1960’s and 70’s. (Ironically, many Koreans even resent Japan for sometimes trying to take too much credit for Korea’s development.)