Barely 24 hours have passed since Japanese mobile gaming firm GREE agreed to a significant tie-in with Yahoo Japan, but already arch-rival and fellow billion dollar giant DeNA has fought back with an announcement that broadens its existing partnership with Yahoo Japan onto mobile devices.

The deal sees the duo’s PC-based gaming service — Yahoo Mobage — take flight to smartphones, tablets and other devices, thereby answering the question of what would happen to the two-year-old joint venture in light of yesterday’s news. DeNA has matched GREE by revealing that it too will interconnect Yahoo Japan user IDs and its popular points system with its own to further strengthen the union and merge user profiles across both services.

DeNA also flashed some impressive statistics, doubtless in response to GREE’s move, and it says that Yahoo Mobage — which it calls “one of Japan’s largest PC-based social gaming platforms” — has more than 9 million registered users. That’s impressive given Mobage, DeNA’s gaming service, itself has more than 45 million users in Japan.

This move is significant for DeNA, as yesterday was for GREE, since Yahoo Japan — which runs independently of Yahoo Inc. — is the country’s largest Internet firm by some way, with 26 million registered users and 2.3 billion page views per day.

As we explained yesterday, both firms are keen to shore up their lucrative domestic businesses to counteract the effects of a ban on kompu gacha, a gambling like mechanism that made DeNA and GREE an estimated half of their revenues in Japan. Yahoo Japan, as a visible and well trafficked site, is the ideal partner to help drive increased traffic in Japan, which continues to be both companies’ biggest money-making market despite their respective international growth.

The deal is another coup for Yahoo Japan which has been busy building its content strategy through deals with Kakao Talk — a Korean messaging firm with 65 million global users — and the $12.8 million acquisition of local mobile content startup Community Factory.

GREE recorded quarterly revenues of $501 million in August but its next financials, due November 14, are speculated to be comparatively weaker. DeNA, however, is on a tear and this week it posted record revenues of $526 million for its Q2 and ploughed a $92 million investment into key game developer and partner Cygames.

Image via J. Henning Buchholz / Shutterstock