Japanese games publisher Konami’s Dragon Collection social mobile game has been a big hit in its native country, with 7m registered players. Now it’s heading to North America.

The game has been released there for iOS, with Android following later this year. It’s the result of a partnership between Konami and fellow Japanese firm GREE, on whose social platform the North American release is running.

Dragon Collection itself is a card-battler game – a genre that’s been lucrative in Japan for a while now, but is also proving popular with Western gamers. GREE’s rival DeNA had a huge global hit with Rage of Bahamut, for example.

GREE and DeNA are competing to sign up established publishers and hot indie developers alike for their platforms in the West, through a mixture of partnerships, investments and acquisitions.

The fact that Dragon Collection isn’t yet available in Europe is a bit of a disappointment though, as GREE is staffing up here as well.