South Korea and Japan normalized relations in 1965, but unresolved historical disputes continue to undermine genuine bilateral reconciliation and optimal diplomatic, security and economic cooperation. Past efforts, both between the two countries and trilaterally with the United States, to help improve relations have generally emphasized a “future-oriented” approach that focused on common security and economic interests. However, the lack of a fundamental and permanent resolution to the historical grievances has also meant chronic bilateral unease and periodic flareups of heightened friction.

U.S. President Joe Biden, center, meets with President Yoon Suk-yeol of South Korea, left, and Prime Minister Fumio Kishida of Japan at the NATO summit in Madrid, Spain. June 29, 2022. (Kenny Holston/The New York Times)
U.S. President Joe Biden, center, meets with President Yoon Suk-yeol of South Korea, left, and Prime Minister Fumio Kishida of Japan at the NATO summit in Madrid, Spain. June 29, 2022. (Kenny Holston/The New York Times)

A Background on Japan-South Korean Relations

The areas of historical tension between South Korea and Japan range widely, including over the name of the body of water separating Japan and the Korean Peninsula (Sea of Japan or East Sea); sovereignty over a group of rocky islets between the two countries (Dokdo/Takeshima); the legality of Japan’s colonization of Korea from 1910-1945; and the treatment of sexual slaves (also known as “comfort women”) by the Japanese imperial military during the wartime period, as well as how the victims’ claims should be compensated and remembered.

These historical grievances often extend into other non-historical disputes, such as Japan’s 2021 decision to release wastewater from the Fukushima Daiichi nuclear power plant and its 2019 tightening of export controls on chemicals necessary for South Korea’s semiconductor industry.

The recent flashpoint for bilateral friction was a 2018 decision by the South Korean Supreme Court requiring two Japanese companies to compensate a group of Korean forced laborers from the wartime period. This decision directly challenged the Japanese government’s view that a 1965 bilateral agreement had settled all claims, including individual laborer claims, “completely and finally.”

Without a fundamental resolution to the historical issues, “future-oriented” bilateral cooperation on diplomatic, security, and economic matters will likely be limited and suboptimal. For the United States in particular, poor relations between its two closest regional allies are not only an irritant but a direct threat to its longstanding aims of developing a network of allies in the region and its present goal of achieving integrated deterrence as part of its Indo-Pacific strategy.

This ongoing USIP essays series seeks to explore new and creative approaches for finding an enduring resolution to Japan-South Korea tensions. USIP’s Northeast Asia program invited subject matter experts to offer a fresh perspective on the challenge by either examining a new approach or a creative take on an existing approach. In particular, the goal was to examine ideas that could have practical policy value for policymakers.

Essay Series

Members of the Korean diaspora protesting the Japanese government’s effort to defund their schools, in Tokyo in October 2017. (Jeremie Souteyrat/The New York Times)

Citizenship Policy Reform in Japan as a Path to Cooperation with South Korea

Erin Chung examines how the ambiguous legal status of descendants of colonial-era Korean migrants in Japan has spurred anti-Korean sentiment among the far-right in Japan, and how reforms to Japan’s citizenship and immigration policies could help resolve this situation and even create openings for greater cooperation between Japan and South Korea.

Demonstrators protest Japan’s decision to remove South Korea from a so-called “white list” of favored export partners, in Seoul, on Aug. 3, 2019.. (Chang W. Lee/The New York Times)

Achieving a More Durable Japan-South Korea Rapprochement

Gregg Brazinsky argues that creating a durable sense of goodwill between Japan and South Korea will require the two countries to listen to dissident voices, look at their history in new ways and convince the United States to play a productive role.

The Japanese photographer Tsukasa Yajima with portraits he took of former Korean “comfort women” at the history museum of the House of Sharing shelter, in Gwangju, South Korea. July 3, 2022. (Woohae Cho/The New York Times)

Different Wartime Memories Keep Japan and South Korea Apart

Daniel Sneider describes how Japan and South Korea have developed separate memories of the wartime period and the colonial rule that preceded and shaped the experience of war, and then offers potential ideas for civil society-based reconciliation efforts that could help bridge the disparate national memories.

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