Ex-Cyber

They certainly did not steal it; the old GiriGiri page links to the Cyberdisc page. As for the copyright notice, a notice alone doesn't really have any legal weight, though it does suggest that they actually got him to sign it over...

A few points to note that many seem to forget when discussing Cassini's legality: - GiriGiri was not originally a Sega product. - There has been no credible evidence presented that the original author (Shinya Miyamoto aka MEGADEATH) completely surrendered his copyright to Sega rather than simply licensing the code. - Internationally recognized copyrights do not have to be registered or renewed and last for a minimum of 50 years. This is mandated by the Berne Convention for the Protection of Literary and Artistic Works, of which all but a handful of industrialized nations are signatories. Basically this says that a work copyrighted in Japan by a Japanese citizen is protected in the US by US copyright law, in France by French copyright law, in Germany by German copyright law, etc. - The previous two points combined with mention in the original tech support email of Sega not renewing the "copyright" strongly suggests that Sega had a license for GiriGiri and not the actual copyright. - That is, there's a very good chance that Shinya Miyamoto, not Sega, is the current copyright holder of GiriGiri.