JR Group announced on November 11, that the Japan Rail Pass will be available for purchase in Japan from March 8, 2017, until March 31, 2018.
At the moment, the Japan Rail Pass can be purchased only overseas before travelers arrive in Japan. During the mentioned period from next March, it will be tentatively on sale in some of the major JR stations in Japan.
At the same time, the Japan Rail Pass will be an exclusive pass for foreign nationals with short term visa. Any Japanese passport holder will be unable to purchase the Japan Rail Pass anymore. Still, until next March, Japanese passport holders who have permanent residency overseas or who are married to foreign nationals living abroad are able to purchase the pass overseas.
For the detail, please visit the official JR Website.
JR East Official Website