Welcome to Gaia! ::

I don't live in Japan, but I have been there on two occasion. One was an extended stay, 2-month homestay. The other was this year in April for 10 days.

As you already stated, language is a biggie. You also need to learn the Japanese terms related to your degree. I don't know all of the regulations, but here are the things to consider:

~ How to get Japanese citizenship
~ Language
~ Housing (Your first month of rent will be equivalent to three-months rent; first month, last month, gift to landlord, and any other deposits.) Do you want to live alone or with other people?
~ Finances and Banking
~ Transportation
~ Special dietary needs
~ Medical insurance

I have a close friend that moved from Japan to Hong Kong, China. He said that moving to Hong Kong is worse. He was living in a serviced apartment for almost 4 months, until he could find a permanent place. It's the way things are for non-natives.

As I told someone else. I would do a homestay first for at least 2-months to do some research and investigated. If you would like more information, I would prefer a PM.