Bitcoin is in many main languages but not Japanese. Why would the guy who created it not make it in his own language? Don't you find it suspicious MtGox is in Japan?
Also the project really isn't a success. A lot of progress still has to be made. Security is still an issue along with sites still growing. Anyone ever even talk to him? I'm not saying he isn't real I'm just putting this out there.
I think you need to read and try to do research before coming here with your less understanding about Bitcoin and it's history. Do you mean Satoshi is not real or you are trying to bring language here. Satoshi was a wise man because he knows that the government is going to come for him, that is why he made everything decentralized even his identity. He showed us how the decentralized world ought to be practically. I am very happy now that upon the government curiosity to know whom he is, nothing is found.