How to get International Health Insurance for Japan & which company to use?

I'm moving to Japan for 6 months. I already purchased my ticket at cheaptickets.com (they don't offer insurance) and was looking at buying int'l insurance separately from online companies, but none of them look trustworthy. Can anyone recommend based on personal experience? Thank you very much!

health-quotes.isgreat.org – try this one.
As I remember they can provide such a service while traveling abroad.