PapayaMobile is launching the Chinese language version of its software development kit today as part of a plan to get more developers to make Android mobile games with its tools.

The Beijing-based company created Papaya Game Engine for Android, a game engine, or tool, to make cool 3D games on Android phones. Now it has targeted China, where there are already an estimated 1,000 Android developers and 20 independent Android app stores.

The company’s platform helps developers make games more social and more viral by adding challenges and leaderboards. Developers using the platform can also cross-promote their games to PapayaMobile’s 8 million registered users. The company says it has doubled the size of its user base since launching the Android social game platform in June.

It will be interesting to watch the growth of the Chinese game developer market. The talent for making cell phone games is spreading around the world, but many of the successful companies have been based in the U.S. and Japan. Game companies such as Ngmoco have been successful on the iPhone, but successes on the Android platform have only just begun to happen. Rovio, for instance, said it published its Angry Birds game as a free ad-supported app on Android and has seen more than 7 million downloads. At some point, the Android market should become large enough to support more Android-focused game studios.

About 20.5 million Android smartphones were sold worldwide in the third quarter of this year, claiming a 25.5 percent market share, compared to just 3.5 percent a year earlier. Apple sold about 13.5 million iPhones, falling from 17.1 percent market share a year ago to 16.7 percent, according to Gartner.

PapayaMobile expects strong growth of Android games in the coming year, particularly in China. To encourage developers further, PapayaMobile is launching a global game developer contest. Developers who use the company’s game engine can enter the contest. First prize will get $10,000, a flight for one member of the team to the Game Developers Conference in San Francisco in the spring, an internship in Beijing for six months, and free promotion on the PapayaMobile home page as Android App of the Day for one week. I am the final judge for the contest. (Rules are here).

Si Shen, a former mobile product manager for Google in China, started PapayaMobile in 2008 with Wenjie Qian. The company has 30 employees and raised $4 million in funding from DCM. More than 100 apps use PapayaMobile’s technology, Shen said. Rivals include Scoreloop, Ngmoco and Aurora Feint.