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 don't understand the connection between satoshi and Japan. Are you just saying the name sounds Japanese so Bitcoin was invented in Japan? Seems like judging a book by it's cover...
Do I find it suspicious that a site called Magic the Gathering Online Exchange is in Japan? No. It was also owned by a Frenchman. Not weird.
You don't think Bitcoin is a success? It's worth nearly a trillion dollars and kicked off a new asset class. It's hard to imagine it being any more successful at this stage. Sure, it's got it's downfalls, but hijacking control to push poor agendas aside, it's growing about as fast as anything could.
Someone had to have written the Whitepaper...