It's here. After one or two extended deadlines, Rakuten Mobile, Japan's disruptive network play, gate-crashed Japan's 4G market today with what it claimed was a "full-scale commercial launch."

Rakuten Mobile wants to shake things up a little. On the back of what it says will be a super-lean cost base, counting operations staff in hundreds rather than thousands, Japan's newbie reckons it will have plenty of legroom to undercut the country's incumbent operations on pricing.

NTT DoCoMo, KDDI and SoftBank will ruefully note that Rakuten Mobile is even more tariff-aggressive than was originally expected.

Referencing growing data demands "spurred by the recent expansion of telework and online education needs" – read COVID-19 – Rakuten Mobile unveiled an "enhanced" Rakuten Un-Limit 2.0 plan to the one it was previously hatching.

As it turned out, the improved debut offer – which probably took a bit of time to plan – was exquisitely timed. On the day before Rakuten Mobile started commercial operations, Japan's Prime Minister Shinzo Abe declared a state of emergency and restrictions on movement to try and stem the tide of new COVID-19 cases.

Under the revised unlimited tariff plan, which still costs 2,980 Japanese yen ($27.60) per month – roughly half what mobile users typically pay to the country's old guard – Rakuten Mobile customers will now get more bang for their yen when going off-net (which will probably happen quite often as the operator still has a lot of basestations to install before achieving national coverage).

Rather than a monthly 2GB data allowance when roaming off-piste into "domestic partner areas," customers will get 5GB. And when that data allocation is used up, maximum downlink speeds revert to 1 Mbit/s rather than the snail-like 128 Kbit/s that was previously on offer.

The core of the Rakuten Un-Limit plan remains the same. Customers will be able to gorge on as much data as they can manage when on the Rakuten Mobile network and make unlimited calls through a communications app called Rakuten Link. The app is based on the previously maligned RCS (Rich Communication Services) technology, which, some say, could now be on the verge of a comeback.

Mavenir Systems is in the RCS supplier mix for Rakuten Link.

Look who's watching
The launch of a new mobile network with aggressive pricing usually has domestic implications only. But the arrival of Rakuten Mobile is not your run-of-the-mill disruptive play.

If Rakuten Mobile can scale deployment of its open RAN tech, both for 4G and 5G (which comes later), operators elsewhere – hitherto reluctant to trust reliability of software and hardware disaggregation in the RAN – may well think twice.

Software company Altiostar is a key Rakuten Mobile partner.

— Ken Wieland, contributing editor, special to Light Reading