Japan's 50/60 Hz dilemma splits the country in half, Tokyo is 50 Hz, Osaka 60 Hz.
One way around it is convert to DC using HVDC stations to tie the grids together The Shinano Frequency Converter
station is one example.
It does limit how much power can be transferred, but changing one side to the same frequency as the other is logistically far worse than LA in the 1940s.
In fact I'm glad LA took care of it before development really got going.