Things aren't that simple everywhere. Electricity transmission in Japan is divided for historical reasons into two regions each running at a different frequency. Eastern Japan runs at 50 Hz, while Western Japan runs at 60 Hz.

https://en.wikipedia.org/wiki/Electricity_in_Japan#Transmission

I had no idea that was an option, but I'm very glad to hear it. Good luck!

I don't know if you're allowed to do that: AFAIK, Kindle book format requires DRM, and Creative Commons licenses (like the one used for OSM) explicitly prohibit the application of DRM to CC-licensed content.

http://wiki.creativecommons.org/Frequently_Asked_Questions#What_happens_if_someone_tries_to_restrict_a_CC-licensed_work_with_digital_rights_management_.28DRM.29_tools.3F