Via Niantic’s official blog, early (closed, presumably) beta testing will commence sometime during March for Pokemon Go.
For those not in the know about software cycles, there is usually an Alpha development phase that only a handful of people get to see. Then comes Beta, before the game goes live. It can be closed (just a select list of participants), or open (open to all), before the final game launch. From the few breadcrumbs given above, and the dozens of articles I’ve read with tiny amounts of detail, I’m going with calling this phase a closed beta. It’s only for Japan.
Not too many details are being shared but all the speculation seems to point to the game in consumers hands worldwide “This year”, meaning sometime in 2016. I’ve heard that one before. Maybe it will be true this time.