Shipping to Japan

My apologies if this has been asked before but does anyone have any experience with (or heard any horror stories about) shipping a cpap machine to Japan?

I've found a supplier that will ship without a prescription but I'm worried about customs and duties. Will I have to produce a prescription from a Japanese doctor to get it out of customs? How much can I expect to get slugged in duties on the way through?

I have only required international shipping once, and so I don’t have much experience with it. My business mostly deals with transfer of good at a local level, and all my shipping requirements are handled by the reliable logistics services Dallas. Have been quite impressed by their services so far.