In his Liberation Day speech, President Yoon Suk-yeol of South Korea pointed out that he would like to improve Korea-Japan relations towards a common future. However, a thorn in the relation between Japan and South Korea has been the unresolved issue of the so-called comfort women who had been forced to serve as sex slaves for the Japanese army between 1932 to 1945. The case of the comfort women raises many legal questions. On December 28, 2015, the Japanese and Korean government reached an agreement that aims to resolve the decades-old problem. The so-called 2015 Agreement gave new impetus to the debate over the legal responsibility of the Japanese government under international law. The most relevant issues and subsequent legal developments will be discussed in the following article.