I haven't bought an instrument (yet) but I have bought things like straps and such. You are buying from a store through the Rakuten site. It was easy, I even changed my order via email after I placed it and there were no problems. International shipping is certainly more expensive but with EMS I've had items arrive faster from Japan than from within the US.
Wick Club member #100 - SSI 5
Lakland Owners Group #166 - DJ5, DJ4, 55-02D fretless, USA 55-69 tetsuya
Zon Club member #11 - Legacy Elite 5
U.S. Peavey Cirrus Club #78