This paper examines the aspects of the border-crossing actions of Korean atomic bomb survivors in South Korea and the solidarity movements that arose in Japan around these actions, with a focus on the “illegal entry” by Son Gwi-dal and the attempt of seeking for medical treatment in Japan by Eom Bun-ryeon and Im Bok-sun in 1968. Using testimonies and writings of A-bomb suvivors, journalists' reports, documentary films, newspaper articles, and diplomatic records, the paper highlights the meaning and historical significance of their crossing-border actions and Japan's citizens' solidarity movements.
 Incident was an act of crossing a boundary drawn by the law and treaty that ignored colonial responsibility, which aimed to “resolve completely and finally” through the Korea-Japan Claims Settlement Treaty. Their atempts to cross the boundary were not only to cross the border established between Korea and Japan, but also to cross the boundary between Japanese victims in Japan and those overseas.
 In the late 1960s, some Korean atomic bomb survivors emerged as people who appealed for compensation to the Japanese Embassy in South Korea, wrote their experiences as victims, or expressed their situation and hopes in meetings, films, and books, rather than being merely objects of pity. We consider Son Gwi-dal, Eom Bun-ryeon and Im Bok-sun's stowaway as symbolic actions that mark the beginning of Korean atomic bomb survivors' emergence as agents.
 Meanwhile, their border-crossing acts greatly shocked those who were engaged in Japan's anti-nuclear power movement or civil society. Those who became interested in Korean atomic bomb survivors recognized their historical significance through their border-crossing acts and introduced their writings and meetings, published books, made and screened films, and sought solidarity with them by reflecting on the nationalistic “peace” that regarded the atomic bombing victims of Hiroshima and Nagasaki as sacrifices of “post-war Japanese” and positioning Korean victims of colonialism in history, thereby questioning the Korea-Japan Treaty System that disregarded colonial responsibility.