The article gives a systematic description of the Japanese policy of prohibiting the immigration of unskilled workers in the face of a world environment that is more and more open for travel, exchange, and communication of all kinds. The side effects of this policy are discussed, as well as three limited quasi-immigration schemes: ethnic Japanese from Latin America, trainees, and students. The exceptional Japanese case is then evaluated on the background of prevailing theories about the necessary tendency to open the wealthy world for more immigration, with a focus on the social welfare implications of the exception.