The rise of new digital technologies and the Internet has given more people than ever before the ability to copy and share music and video. Even as Japan has adopted stronger copyright protections, the number of Japanese peer-to-peer file sharing network users has multiplied. Though the distribution of copyrighted material online has long been illegal and, as of 2010, the download of copyrighted material is now a criminal act, illegal file sharing continues apace, with the majority of people active on Japan’s most popular file sharing programs remaining unaffected by the new legislation. Clearly the law alone does not work to constrain file sharing behavior in Japan and, in fact, it is not the only way Japan strives to enforce copyright law on the Internet. What strategies are industries and government taking to curb illegal file sharing and are these strategies effective? How is unauthorized peer-to-peer file sharing cast into an act both immoral and worthy of criminal prosecution? Of particular interest are the evolution and growth of architectural and social constraints on online behavior alongside these legal constraints. / text