A skinny chain smoker with pale skin, Yota Kachi doesn't look much like a professional athlete. But this weekend, the 31-year-old will get a chance to become one by playing video games.

Japan will begin the process of legalizing paid esports with a tournament near Tokyo that kicks off Saturday. Hundreds of players, including Kachi, will face off in a two-day competition for more than $300,000 in prizes from game makers including Sony Corp. and Mixi Inc. But the true stakes are even higher: The top few dozen players will get licenses to play in paid video game competitions in the future.

This is a seismic shift for Japan. Laws meant to prevent illegal gambling have in turn restricted paid gaming tournaments in the country, even as gamers in China and the U.S. have won fame and fortune. The new system is aimed at giving Kachi and his peers the chance to make a living by doing what they love and helping domestic software developers join a multibillion-dollar global industry that's so far left them behind.