The partnership between gaming firm DeNA and Yahoo Japan appears to be bearing fruit after the joint Yahoo Mobage service passed 10 million users in Japan, according to an announcement in Japanese.

The two companies furthered their existing partnership in early November and have since added one million new registered members to the two-year-old joint service over the preceding two months.

The updated agreement – which came just one day after GREE partnered with Yahoo Japan — will see Yahoo Mobage expand from just serving PCs to arrive on mobile devices soon. The two firms also agreed to interconnect Yahoo Japan user IDs and its popular points system with DeNA’s own to further strengthen the union and merge user profiles across both services.

DeNA’s Mobage service remains the priority, however the company is less communicative with its user numbers for that. Its latest data, from last year, says it has more than 45 million users but, if Yahoo Mobage can add 1 million new users in two months, it’s likely the standalone service is seeing stronger growth in Japan, not to mention growing adoption overseas.

Yahoo Japan is an ideal partner for DeNA and GREE since it is the most popular Web portal in the country and can provide a significant amount of visibility, traffic and new gamers. Indeed, Yahoo Japan has some 26 million registered users and enjoys 2.3 billion page views per day.

The companies say that Yahoo Mobage is Japan’s biggest social gaming service for the PC, and they are celebrating the 10 million milestone by giving away $4.9 million of prizes to users this month.

Image via The Asia Career Times