Japan–Korea relations

The modern relationship was formalized in 1965 with the Treaty on Basic Relations, which restored diplomatic ties after decades of estrangement following Japan's 1910–1945 colonial rule over Korea.¹ The treaty included a claim settlement of $300 million in grants and loans, but it did not resolve lingering grievances over forced labor and sexual slavery, which continue to fuel disputes.² Earlier, in 1910, the Japan–Korea Annexation Treaty formally colonized the Korean Peninsula, a period marked by cultural suppression and economic exploitation.³ The 1965 normalization was driven by Cold War geopolitics, with the United States encouraging both nations to align against communist threats. However, the treaty's legacy remains contested, as many South Koreans argue it failed to provide adequate compensation or acknowledgment of wartime atrocities.

Territorial and historical issues regularly strain relations. The sovereignty over the Dokdo/Takeshima islets, administered by South Korea since 1954, is a persistent point of contention, with Japan claiming them based on historical records. The comfort women issue—referring to women forced into military brothels during WWII—has led to diplomatic clashes, including the 2015 agreement that was later criticized for lacking victim consent. In 2018, South Korea's Supreme Court ordered Japanese companies to compensate forced labor victims, prompting Japanese retaliation and a trade war that disrupted global semiconductor supply chains. These disputes are exacerbated by nationalist politics on both sides, with leaders often using historical grievances to bolster domestic support.

Despite political friction, economic ties remain deep. Japan and South Korea are each other's third-largest trading partners, with bilateral trade exceeding $80 billion annually.⁴ They are also intertwined in global supply chains, particularly in electronics and automobiles, with companies like Samsung and Sony relying on cross-border components. Security-wise, both nations host US military bases and participate in trilateral exercises with the United States, though historical distrust limits deeper military cooperation. In recent years, they have cooperated on North Korea's missile threats, sharing intelligence under a 2016 agreement that was later terminated in 2019 but revived in 2023. Cultural exchange is also significant: South Korean pop culture enjoys a large following in Japan, and vice versa, though this is sometimes overshadowed by political animosity.

Beyond headline disputes, several lesser-known dimensions shape the relationship. The 2002 FIFA World Cup, co-hosted by both nations, briefly fostered a spirit of cooperation, leading to joint cultural events and youth exchanges.¹ The Zainichi Korean community in Japan, numbering around 500,000, faces discrimination and identity challenges, yet serves as a bridge between cultures.² In the 1970s, a secret normalization attempt with North Korea was aborted due to Japanese public backlash, illustrating the complexity of inter-Korean dynamics. Additionally, the Dokdo dispute has spawned a niche tourism industry, with South Korean visitors flocking to the islets as a patriotic act, while Japanese textbooks often omit or downplay the controversy. These subtleties reveal that the relationship is not monolithic but a tapestry of historical, social, and economic threads.

Comfort women

Women and girls forced into sexual slavery by the Imperial Japanese Army during World War II.

Dokdo/Takeshima

A group of small islets in the Sea of Japan, controlled by South Korea but claimed by Japan.

Zainichi

Koreans who reside permanently in Japan, often descendants of colonial-era migrants.