It is now illegal to mod game save data and game consoles in Japan. Both are punishable by up to five years in prison and fines up to 5 million yen ($46,000USD).
According to the official site for Japan’s Association of Copyright for Computer Software, modding game save data and consoles violate the country’s Unfair Competition Prevention Law. The Japanese government is expanding its regulations to protect game console content. The Association of Copyright for Computer Software also mentions that unofficial software codes and keys are also illegal. Specifically, mentioned is offering these on online auctions and making them available for download.
This was first published by Japanese game sites like Hachima Kikou after peripheral maker Cyber Gadget stopped selling its Save Editor data tool, which allows players to use cheats and patch codes.