Can you get Working Holiday Visas in the states? In the UK, you can, and that's how I got into Japan for a year.
Basically it's an extended tourist visa that allows you to work, but you don't have to. It's perfect if you want a flexible year in Japan to help you find your feet and really decide if long-term work in Japan is right for you. I had a job lined up anyway when I got mine, but a housemate of mine was also on a WHV only without a job lined up before. He ended up working with us, however.
Not to discourage you, but I too would like to emphasise what others have been saying about Japan not exactly being a fairyland which you'll immediately feel at home in. Not just because of the long work hours and high suicide rates, but just because of the general differences in culture. It's massively different in big ways and small ways you'd never expect. Adjusting to it as a tourist is one thing, but adjusting to it as somebody who lives and works there is another. I'm not trying to scare or discourage you. In fact, I'm trying to encourage to be prepared for the difficulties that lie ahead. You can overcome them, but be ready.
All the best
