The Kyoto District Court has fined Mr. Isamu Kaneko, a former University of Tokyo researcher, for developing the anonymous file-sharing software Winny. It ruled that development of the software program, in effect, helped users illegally copy copyrighted content.

It is the first guilty sentence in Japan handed down to a file-sharing software developer. It is intended to serve as a warning to those who would encourage the spread of illegal copying among Internet users. But it could also discourage engineers and researchers from making efforts to develop new, useful software since they may be charged with assisting crimes.

Winny makes it possible to anonymously exchange documents, music, images and other files among computer users, not through a server but through a computer network. Users designate files that can be copied and other users search for such files on the Internet and download them free of charge. Mr. Kaneko posted Winny on his Web site in May 2002. The court decided that he continued to post the program while aware that it was being used in illegal copying of copyrighted content. It condemned his act as "self-flattering and irresponsible." Copyright damage caused by Winny is estimated at about 10 billion yen.