I'm not one of those guys who is obsessed with Japanese life so much that the only music I listen to is Japanese music or anything from East Asia, but I do listen to music in different languages from time to time. I have been particularly into the raps of a Japanese dude called 環ROY (pronounced Tamaki Roy) who seems to always make awesome tunes and he has a pretty good flow (even though I can't figure out a word he is saying, maybe one day I will master this bizarre language and find out he is actually rapping about porn or something). Here is one of his tunes along with two other dudes: Rau Def (He has another good song that I like called 'Dream Sky' and Ski-Hi (I didn't know who Ski-Hi was until I found out about this collaboration). The tasty beat and also the catchy vocals in the chorus (I think) were supplied by a bro called Sunny Boy. Give it a listen, you will be impressed.