http://www.japantimes.co.jp/news/2011/07/19/reference/japans-incompatible-power-grids/
Did you know that half of Japan runs on 50Hz AC electricity while the other half runs on 60Hz? I did not know that! That does finally explain why it was such a big deal that their east-coast reactors went offline after the tsunami - they were unable to import excess electricity from the other side of the country (which, since Japan is pretty skinny, really isn't that far away).
I guess that's why most AC adapters sold there had switches... it makes sense now
Yeah, It's pretty crazy.