I'm going to the Rising Sun Rock music festival here in August, it's only Japanese musicians so I made a couple of 8track mixes to help out the friends I'm going with. It's a pretty varied selection if you want a sampler of contemporary Japanese music: jazz to jazz-punk to electro-pop to retro-punk to electro-punk to downbeat-electro and all that noise in between.
(edit: Oh hey, a couple of THESE were in my last mix, too)
Saul Williams- Black History Month Art-ish hip-hop with production by Trent Reznor
P.O.S.- I Play The Matador (Redo version) Aggressive punk rock-influenced (P.O.S. is a member of Building Better Bombs) alt-rap. I wish more of his tracks had this kind of kick to them. It fits his style and his roots quite well.
Grand Buffet- Dark Autumn Using 'hip-hop' loosely here, but it's what they go by. Not sure if they're taking themselves seriously or not, but it works either way.
Lady Sovereign- Fiddle With The Volume Well, it was either her or mc chris, and I'm not sure how I feel about him these days.
Doomtree- Kid Gloves P.O.S. makes another appearance here. Alternative rap collective from Minneapolis. Pretty sure this album is right behind Method Man and Redman's 'Blackout!' on my list of favorite hip-hop/rap albums.
The Coup- My Favorite Mutiny Featuring Black Thought and Talib Kweli. I wish The Coup were a better group, because the handful of good songs they have are really, really goddamned good. ....I feel that way about too many bands I listen to.
Busdriver- Imaginary Places C'mon, how can you not like this?
RJD2- Ghostwriter Hip-hop instrumentals. This dude makes catchy stuff.