It's J-Rock, not pop, NOT metal. Although it is very poppy rock. I went through a J-Rock stage a LONG time ago, and I still listen to Dir En Grey from time to time, if you don't know them:
[ame]http://www.youtube.com/watch?v=EUvpMhw5ALw&has_verified=1[/ame]
Also Japan has 1 and only one metal band I enjoy, a very quintessential Melodic Death Metal band called Serpent:
P.S. This thread should probably go in a non-metal section.