May 21, 2024

Japanese P2P Author Arrested

Japanese police have arrested the author of Winny, a peer-to-peer application popular in Japan, according to a story on ABC News’s Australian site. (Reportedly, a more detailed article is available in Japanese.) Isamu Kaneko, a 33 year old Computer Engineering “guest research associate” at Tokyo University, was arrested for conspiracy to infringe copyright. If convicted, he faces a maximum penalty of three years in prison. Winny’s author had previously been known only by the online moniker “47,” but police apparently used the records of some kind of online bulletin board to identify him.

UPDATE (10:20 AM): Corrected Mr. Kaneko’s job title. I originally wrote “graduate student” based on the ABC article, but Seth Finkelstein pointed me to an authoritative page at Tokyo University with the accurate title.


  1. punisher says

    Winny is a Japanese peer-to-peer (P2P) file-sharing program which was made as a poor imitation of Freenet network and which claimed to keep user identities untraceable not for freedom of speech but for hiding crime. The developer of Winny had never said about freedom of speech.

    The software takes its name from WinMX, where the M and the X are raised one letter in the Latin alphabet, to N and Y. As of September 2003, there were 250,000 users of the program according to the Tokyo-based Association of Copyright for Computer Software. According to P2Pnet, it is the most popular file-sharing program in Japan, with eDonkey and WinMX in second and third place respectively.

    The software was developed by Isamu Kaneko, who is a research assistant in graduate course of computer engineering at the University of Tokyo in Japan. Kaneko originally anonymously announced his intent of developing the software on the popular 2ch Japanese bulletin board site, but this board named ‘Download Software BBS’ was filled with many copyright violation criminal users. As one of 2ch’s cultures include referring to anonymous posters by their post number, Kaneko became to be known as “Mr. 47” (“47-Shi”, or 47氏 in Japanese), or just “47”.

    On November 28, 2003, two Japanese users of Winny, Katsuhiko Kimoto, a 41 year-old self-employed businessman from Takasaki, Gunma Prefecture, and an unemployed 19-year-old from Matsuyama, were arrested. They were accused of sharing copyrighted material via Winny and admitted to their crimes. The police tracked the users via Winny’s transfer,since the cipher for anonymity was decoded.

    The police searched home of Kaneko and his university, because he had also developed and experimented about Winny at university. On May 10, 2004, Kaneko was arrested for aiding and abetting copyright law violation for arrested two Japanese users of Winny of many copyright violation criminal users in ‘Download Software BBS’ by the High-tech Crime taskforce of the Kyoto Prefectural Police.

    His developing of Winny at the criminal board is main reason for having be regarded as aiding and abetting copyright law violation. This police act doesn’t mean general developer’s crisis. The developers of other P2P of Japan aren’t accused by any crime. They released their P2P software on general website, but Kaneko released Winny at the criminal board of copyright law violation.

  2. anonymous says

    if you know this P2P software called “Winny”,
    you will amazed how good it is.
    It makes THEM blue & numb, so turned out to
    be this arrest.

  3. Now, Kaneko’s friend has launched a WEB site
    to support him.

  4. According to, even in the U.S. there could theoretically be problems for file sharing developers, at least to the extent of civil liability.

  5. See, there still are some good reasons to live in the US!

  6. From that second article:

    “Basically, what I did clashes with the law, so it was almost inevitable that I was going to be arrested,” Kaneko told the police.”

    Also coverage here:

    General comment: I wish people would finally understand how legally risky has been my censorware work, and why I had to quit from lack of support, even for my DMCA exemption efforts :-(.