In my July 19 column in The Japan Times, I write about how the heck Japan ended up with two separate electrical grids, a topic very much in the news because the incompatibility of the grids greatly exacerbated the power shortage that resulted from the March 11 earthquake and tsunami. (And while we’re on that topic, please check out my updated list of power-saving tips specific to Japan.)
The diagram above shows the dividing line between the grids. All the electricity to the west (left) of the line operates at 60 Hz, while everything to the east (right) runs at 50 Hz. But the truth isn’t quite that neat. What that diagram doesn’t show is that Nagano Prefecture is a kongō chiku 混合地区, or all mixed up. Most of the electricity in the prefecture oscillates at 60 Hz, but the municipalities shown in green on the diagram below, borrowed from Chubu Electric’s website, get their juice at 50 Hz. Now wouldn’t you like to know how the heck that came about?