Client Nokia is going to start their own cell phone service in Japan as an MVNO, largely to position and market their higher end phones reports Reuters.
Japan is known for being one of the most advanced mobile societies. I remember a Japanese businessman showing me how he uses his phone to gain access to his apartment, make purchases using an embedded (RFID?) chip and more a few years ago.
Japan is also one of the largest markets for wireless data and yes, VoIP, with Yahoo BB.