Under current Japanese, it is illegal to upload or sell pirated games and movies. It is legal to copy for one's own personal use. Better get all your personal copying done pronto, because that's going to get harder.
According to the Asahi Newspaper, Japan's Agency for Cultural Affairs is readying new legislation that will revise the current copyright law that will prohibit the creation and distribution of software copying programs. The new upcoming revision, however, does not list penalties for the act of copying itself.
Currently, such copying software is readily available online and not prohibited — nor is duplication for home-use.
These new revisions don't stop at DVD copying software, but also encompass devices like the R4 in that the law would be expanded to ban the production of devices that enable pirated game software to run on consoles.