I'm used to things being expensive in Japan, but usually I justify the price because I'm getting something I enjoy. "Enjoy" and "moving" don't go together.
Step 1: Get price info to ship items back home. (Not everything will fit in my suitcases) For reference, 10 kg = 22 lbs.
Airmail M-bag (Printed Matter Only) 9000Yen
Airmail Parcel (Printed Matter Only) 2 x 4250Y = 8500Y
EMS expdited delivery (2-4 days?) 14000Y
Parcel Post Airmail (7-14 days?) 17650Y
That seemed pretty pricey, so I checked another option: the equivalent of UPS, Yamato kuroneko "black cat" service. I sent them email, but they never sent back to me. (First warning!) A week later I called, but they elected to call me back, in order to have the phone call in English. Next day they called, and I gave them the rough estimate of my boxes. (Roughly, 4 10kg boxes). Price estimate, by Air: 150,000 Yen!
... and finally, for comparison, checking out the price of the reverse trip, US -> Japan, using the good ol' US Postal Service:
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So... for all those concerned, all options are expensive (SHOGANAI! = apathetic "What can ya do?"), but the Japan Post Office is the way to go. They have the cheapest option I can find, especially these days, if you consider that the Yen has been weak. (The price for 22lbs by EMS is about $118 USD, respectfully in range with $99.70 above) ... 20% more than I'm used to isn't nearly as bad as 240% the price!
Uhg.. these boxes are heavy. Kilograms are deceptively large, for a person accustomed to lbs! I'm off for the PO..