I'm sure there are FG's who have moved to or from Japan and worried whether they were getting scammed or were using less than reputable movers. If you want to protect yourself, I recommend checking out http://www.movingscam.com/
The above website is American-centric and focuses on US regulation of domestic movers but has worthwhile tips on planning an international move that anyone can relate to and has a blacklist of moving companies that are known to cause problems for the innocent consumer. There also is a great forum populated by some experts in the moving industry who will respond to PMs if you have specific questions.
Unfortunately, there are a lot of scammers in the US moving industry due to reduced governmental oversight. I'm not affiliated with that site at all but have relied on it for advice relating to a couple of domestic moves. The mods on that site saved my ass recently by diverting me from using a mover they found to be questionable.