The Japanese Hip-Hop Scene

I plan on visiting Japan this December and as a beatmaker (predominately hip-hop), I'd like to know it's current impact in Japanese culture right now. Who would you consider popular? Or someone to look out for?

I am a complete beginner at this business.
But I heard they are very popular.

"miss you" by m-flo loves melody.&Ryohei
http://www.youtube.com/watch?v=KD59LJX2r38

"JUVES" by Diggy-MO'
http://www.youtube.com/watch?v=Z5azaJ1FrVM
"ALIVE" by SOUL'd OUT
http://www.youtube.com/watch?v=BrqUC3neqdw
"VOODOO KINGDOM" by SOUL'd OUT
http://www.youtube.com/watch?v=utso4K1nJzc
"SunRise" by BENNIE K
http://www.youtube.com/watch?v=swKMrnWDt_0

And BeastieBoys x DaftPunk x Capsule...?
http://www.youtube.com/watch?v=WRvipYTeVp0

This youtube user MrMaru0712 does some good compilations of current tracks.

http://www.youtube.com/user/MrMaru0712/videos?flow=grid&view=0

There are full track listings so you can just search youtube for that specific artist/track to see the video or their other videos.

Here's an example of a track:-
http://www.youtube.com/watch?v=sozmNUDLPqg

I assume you will check out a few clubs while you are there. Places like Harlem might suit.
http://www.harlem.co.jp/

And you can also check the gig guides like:-
http://metropolis.co.jp/
http://www.tokyogigguide.com/
http://www.clubberia.com/en/

Enjoy your trip!