The ZIP file contains the following types thin, light, regular, medium, bold, heavy and black
Copyright (C) 2002-2016 M+ FONTS PROJECT
These fonts are free software.
Unlimited permission is granted to use, copy, and distribute them, with
or without modification, either commercially or noncommercially.
THESE FONTS ARE PROVIDED "AS IS" WITHOUT WARRANTY.
http://mplus-fonts.osdn.jp/about-en.html