Unlike any other country in the world, Japan has two completely separate, incompatible electrical power system. The east of the country, Tokyo to Hokkaido, operates on 50Hz whereas the west, Osaka, Nagoya, Hiroshima, operates on 60Hz. Modern appliances are designed to accommodate both but my old turntable sits in the closet, love but unusable.
The history of this dates back to the late 1800's and the first attempts to electrify the country which was a somewhat entrepreneurial time. As usual Tokyo and Osaka were in competition and Tokyo decided to import German made AC generators operating at 50Hz whereas Osaka equipped the city with American generators operating at 60Hz. Small, localised services expanded over time until slowly everywhere was illuminated. And they've been different ever since.
Japan's electrical Mason-Dixon Line bisects the country through the Shizuoka and Nagano prefectures. West of the Fujigawa and Itoigawa rivers the country is 60Hz and east it's all 50. Even following WWII the political will simply wasn't there to choose a single standard. The upshot would have been that half the country would need to replace every household fixture. A politically and economically unbearable decision.
And so Japan remains disunited, unable to transfer power across a river. And my turntable will remain in it's box, out of sight, but not out of mind.