I'm a big fan of Japanese music so most of what I like is unknown here since, unlike Korea, their music industry doesn't reach global audiences (despite being the 2nd biggest music industry in the world)

But there's a few bands I like which are fairly unknown even over there. Marie Ueda is fantastic. I can't think of a bad song of theirs. They've do alt rock music and I love it. Also the singer does some great solo acoustic and acoustic guitar supported by piano stuff.