USA (110-120 VAC, 60 Hz) three prong and two-prong grounded
Note one blade is wider at end of two-prong plug
Japan (100 VAC, 50~60 Hz) on USA converter plug
Note blades are same dimension, no wodening
*Eastern Japan 50 Hz (Tokyo, Kawasaki, Sapporo, Yokohoma, and Sendai);
Western Japan 60 Hz (Osaka, Kyoto, Nagoya, Hiroshima)
Voltage is generally a problem; Hz / Cycles per second
can be with some items (usually motors)
Best site for plug issues:
http://www.kropla.com/electric2.htm (Also see their telephony pages)