Japan Mobiles
This Thread covers Mobiles / Mobile Services in this country, including typical usage, services available, and so forth.
Japan's changing mobile market
After a decade as Japan's dominant provider, NTT DoCoMo can no longer say it provides most Japanese with their mobile phones, with smaller rivals grabbing share in a fierce fight ahead of the start of the academic and business year.
Ref. https://www.stuff.co.nz/4470399a28.html
For more information on Japanese Mobile Services please visit the Japan Index.