Yep, it will be a culture shock, that's for sure. The average English teacher lasts between 6 months to a year here. Get on the Net and check out the many forums out there...here is one
www.gaijinpot.com.
You don't have to know how to speak/write Japanese but the basics will help. Your school will help you get set up with your Visa, bank, alien registration, water/hydro bills, etc.
Catback is right saying many don't care enough about it (English) to learn it. They spent to most money learning English and rank near the bottom in Asia in ability. It's amazing.
Basically, your enjoyment or disagreement with the country will depend on your school. There are lots of great places, many good places and tons of shit places. You will have to do a lot of research before you go if you are serious about coming here.
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Life's jounney is not to arrive at the grave safely in a well-preserved body, but rather to skid in sideways, totally worn-out shouting, "Holy sh*t! What a ride!" - unknown
