I lived in Japan for 9 years and travelled to every prefecture, AMA.

I had kind of a nontypical experience there to be honest, I had a job through the air base - they hire a lot of Americans to move overseas or already living overseas. The work itself wasnt bad, and it was nice to be able to work with local Japanese hires that knew English or the occasional Google translate app to start. From what I have heard from some of the other Americans/Japanese coworkers it is really dependent on what you want to do. Some companies just want a foreign face to seem like they have more of a global presence, so you are kind of there for show, others don't overly care as long as you have a working knowledge of the language. You might be surprised how quick you could pick up the language though, I worked with a few people who got married to a local without knowing the language, then were basically fluent after a year.

/r/AMA Thread Parent