"There isn't G-rock for Germany" ...but there IS [tag]German rock[/tag], and [tag]Deutschrock[/tag]... also, there is a song by a German band all about a girl who only listens to German rock: [track artist=Die Ärzte]Deutschrockgirl[/track].
Jrock ISN'T just plain rockn' roll. It's Jrock.... =P It's developed in it's own individual way that is independent of American rock with influences from non-rock Japanese music and culture. Just like you have classic rock and hard rock and psychedelic rock and prog rock and alternative rock and different kinds of metal (because they've deviated beyond the idea of just plain "rock n' roll)... Lumping it all together doesn't prove anything or serve any purpose and doesn't help anyone. It's not all just rock n' roll. Call it just plain rock or rock n' roll if YOU want, but don't talk about the genres being pointless in general if you don't understand what they are and why they're called what they are.... Arg, this really annoys me....
Just because music is Japanese doesn't mean it has to be labeled as a 'kei' as with bands that originated in the visual kei scene (MUCC, DeG, etc)
A lot of this music is rock, just simple rock music. You don't need to label it as "Jrock" because no anywhere else calls our music "A-rock" or "USA-rock". There isn't G-rock for Germany, or Mrock for mexico, its just rock n roll.