I honestly don't know. My assumption would be that they play games at more/less the same rate as everyone else, but mostly play domestic products - like everyone. They're a country with a distinct identity and their own language/history/culture. I'd imagine Japanese products written for Japanese people by Japanese people would be the most popular, over something like D&D.

Like I said that's my guess, I really have no knowledge of it. However this is the Internet and I'm sure somebody knows or has experience. I'm mostly just posting so I can find out fairly how wrong my impression are without the benefit of hearing the real answer.