both the DMCA in the US as well as that Japanese law are implementations of the 1996 WIPO Copyright Treaty. that is why they can be discussed in a fairly interchangeable way.

Which law exactly?

the paragraph after the one you quoted answers this question:

Note that this discussion was based on Japanese law, but the same language is found in the DMCA Section 1201(a)(1)(A): “No person shall circumvent a technological measure that effectively controls access to a work protected under this title.” That law is more than 26 years old, going into effect a month after Google was founded, but the language remains in place.