[Firebird]

It is not a working visa its a working holiday Visa wich permits you to do most jobs for up to 1 year, after that you would have to find a sponsor if you want to stay longer. You need to be 18 for this Visa!
I do not know if you can get a scholar ship after that year but you would be sure if you really like it and if its worth fighting for.

Another option is to do it like MMM said and finish college and do a degree and than try and find a real job.
What i wanted to say is, you can do a "trial run" in that year, work a bit to survive and see if you really like it. Because maybe (most definetly) Japan is different from what you imagine it, and on a 2 week holiday you will not see Japan as if you life and work there for a year.