There is another way to move to Japan, and that is through a U.S. government job. I don't mean military either. The U.S. embassy contains staff from numerous civilian agencies that includes non-special agent positions, known as "professional support staff".
For example the FBI Legat offices located all around the world. These offices have a few agents, but also normal non-agent support staff:
http://www.fbi.gov/contact/legat/legat.htm
And from the inside let me tell you that a lot of these support staff personnel do NOT possess any language ability for the country they are assigned too. In fact, from speaking with the head Special Agent of the Tokyo Legat (basically stands for legal attachment), he informed me that none of his support staff have any Japanese ability......even though it is listed as a very desirable skill during the selection process. The reason is because most of the government, well at least the FBI, now contracts out it's linguists. That means most of the people who would come to work for the FBI due to their great Japanese ability won't actually be official FBI employees, and thus aren't eligible to work in a Legat office.
So what this means is that if you can get on with the FBI in any capacity as an official employee, even if you start as a "lowly" office clerk, and have some language ability on the side, you might actually have a pretty decent shot at an overseas office after just a couple of years. As a side note the competition for offices like Tokyo is also VERY low from what I hear......as in sometimes only one or two people apply for it when openings come up lol. Most adults never think twice about Japan and simply want to grab one of the European openings. That and most people in the FBI have family so they simply don't apply for any legats in the first place.
This of course kind of blows my mind because the setup is pretty much a dream job.
You get a paid apartment in Akasaka about 2-3 times the size of what a "normal" single Japanese person would have, which isn't surprising since the housing allowance for a single person is around $70,000
per year.
Your base government pay + an additional $1,000 per month........tax free.
They'll pay to send your kids to school and pay for you to go to language school or to complete your bachelors or masters degree while you are there.
So basically you get everything for free and your paycheck is pure spending money.
This is just for the FBI of course, but there are several other agencies with similar setups.