This article describes Japanese corporate and state involvement in the development of the South Korean sex industry in the early 1970s. It suggests kisaeng tourism generated demand for the prostitution of South Korean women, as well as facilitated the transmission of Japanese corporate prostitution practices to South Korea. The role of the Japanese tourism industry and the Japanese government in supporting the emergence of kisaeng travel is also considered. The discussion draws on document-based sources to examine Japanese involvement in South Korean sex industry development from the theoretical perspective of cross-country patriarchal collaboration. It asks, What interest did Japanese state and corporate actors have in collaborating with South Korean government and industry to facilitate the development of the Republic of Korea’s (ROK) local prostitution industry and to secure Japanese male sexual access to South Korean women in the early 1970s? The resulting discussion contributes to the development of a feminist “international relations” (IR) critique of prostitution.