I don't wish to split hairs here, but I don't like the term "J-Rock." It implies that rock music from Japan all sounds similar enough to constitute its own genre, when it is actually very varied in sound. I notice it only happens to Japan, too... I never see music from England being called E-Rock. Franz Ferdinand isn't G-Rock (Glasgow rock). (There was the Britpop movement in the '90s, but that had a definable sound.)
What in the... hell?
No, really... Jrock is Jrock. Get the fuck over yourself.