Why are Roombas so expensive in Japan?

We've recently been thinking it would be nice to get a Roomba to keep HQ clean, and figured given the US pricing that we'd be able to pick one up for perhaps Y20,000-Y30,000. We were in for a shock.

A quick look at some Japanese online shopping sites shows that prices for officially-imported Roombas in Japan approach 3X those in the US. A Roomba Red that currently sells for US$149.99 on Amazon will set you back at least Y46,980 on Rakuten (an online mall that's usually a standout for its low pricing). That's just over US$400 at today's exchange rates. Higher-end models run to more than double that price.

This kind of differential isn't unknown in Japan, but it's intermittent. On the whole, where there's an official distributor -- as with the Roomba -- our experience has been that prices tend not to be extortionate, except for items like clothing and leather goods that carry hefty import duties. So why does the Roomba cost 2X-3X as much here? There's presumably some overhead for localizing the documentation, and possibly for regulatory approval, but it's hard to believe that would double the unit cost, and easier to think that the company and its importer see the pricing point as being acceptable here. We'd be interested to be proved wrong.

Anyone in Japan and similarly unwilling to part with the sums described above for a Roomba can draw some consolation from a site called Shop.com, who we don't know from Adam, but are offering Roombas more or less at US pricing (say Y18,000 for a Red). Caveat emptor, and all that.