This study examined how the experience of ‘East Sea’ as a border or sea boundary affected identity building among Korean residents in Japan, mainly on minority magazine media of Korean residents in Japan, which were issued around December, 1959 when the first returning ship started from Niigata port in Japan to Cheongjin port in North Korea. It was found that many Korean language magazines under Jochongnyeon mentioned uncertainty of returning home, and recognized ‘East Sea’ as a place for liberation which heal ‘sadness’ and ‘anger’. In addition, from the early stage of returning, Kim Dal Soo who spoke for Korean residents in Japan in Japanese majority media made public the fact that not only Korean residents in Japan, but also many Japanese wives return to North Korea. However, by connection and interpreting piece by piece the language identity building process of himself and Japanese wives, and caused the result of covering uncertainly and political nature implied in the return project.