Horaay. Possibly my most obsessed-over Japanese group.
Yeah. Number Girl. They mix a very distinct rock sound (think The Pixies or Sonic Youth on some Asian form of crack) with a very distinct Japanese sound (pentatonic! Using only a specific five notes from a scale. I love it in rock music. Thus what I meant by "Asian crack"). Their lead guitarist collaborated with Shiina Ringo, thus how I discovered them. In fact, so did their vocalist/rhythm guitarist, Mukai. But stuff.
I also tend to occasionally obsess over their drummer, Inazawa Ahito, for being a) awesome b) collaborating with everybody and their mother, including Shiina Ringo and another fairly bizarre and almost Debussy-esque group called Luminous Orange.
But you don't care about names. You care about sounds. Sounds!
mp3: Number Girl - Super Young
mp3: Number Girl - Mangasick
mp3: Number Girl - Yaruse Nakio no Beat
In addition to the very good blend of sounds and the pentatonic stuff, there is a lot of musical and rhythmic juxtaposition between the two guitars, and in the rhythm section. Juxtaposition pleases me greatly.
Number Girl disbanded in 2002, only for the members to go off and form a bunch of other really insane-but-awesome ensembles. So clearly it wasn't a completely sad thing.