If there’s one market where Twitter is pummeling Facebook, it’s Japan.

Unique users are up to 7.52 million compared to Facebook’s 1.4 million, Nielsen Online Japan told The New York Times. Even third-party Twitter developers are seeing some of the action; HootSuite’s chief executive Ryan Holmes told us that roughly 30 percent of his service’s month-over-month growth is coming from Japan.

So it made sense for the microblogging network to secure a mobile deal to further ingrain its presence into everyday life the way that rival social network Facebook has through partnerships with U.S. mobile carriers. Twitter has partnered with Japan-based wireless carrier Softbank to create a line of handsets that link to the service. Fourteen of Softbank’s upcoming phones will be Twitter compatible and will offer an icon on the homescreen that connects directly to a Twitter site.

Part of Twitter’s success in Japan has to do with the language. The service’s 140-character limit isn’t so restricting in Japanese, since words can be compressed down to two or three characters. As a result, tweets can be much more expressive. As in the U.S., celebrities and politicians have also taken to the service to communicate with fans and constituents. That international growth has fueled Twitter’s overall user acquisition rate, clocking in at about 300,000 new registered users per day, or a little over 9 million per month. Facebook, by comparison, has been pulling in roughly 25 million a month for the last year or so.