In japan they have different frequencies.. and a Voltage of 110 Volts. Due to voltage fluctuations the voltage can be between ~95 and ~120 Volts...
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east japan 50 Hz (Tokio, Kawasaki, Sapporo, Yokohama, und Sendai)
west japan 60 Hz (Osaka, Kyoto, Nagoya, Hiroshima)
A-Type plugs and sockets are most common over there but they also have B-Type with PE which is less common.
They have the B and Y distribution system in japan
Y = Three-phase system
B = One-phase system
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On basis of your first post you must be from the us or canada. In that case you should bring an A-Type Plug but if you want to be on the save side take a B-Type as well with you.