TheTechMatterAnswer: Japan Travel & Internet survival guide

The voltage in Japan is 100 Volts, which is different from North America (110V),Central Europe (240V) and most other regions of the world.

Japanese electrical plugs have two, non-polarized pins, as shown below:

They fit into North American outlets. Japanese power outlets are identical to ungrounded (2-pin) North American outlets. While most Japanese outlets these days are polarized (one slot is slightly wider than the other), it is possible to encounter non-polarized outlets in some places.

Some North American equipment will work fine in Japan without adapter and vice versa, however, some sensitive equipment may not work properly or even get damaged. If you intend to purchase electronic appliances in Japan for use outside of Japan, you are advised to look for equipment specifically made for oversea tourists.

The frequency of electric current is 50 Hertz in Eastern Japan (including Tokyo, Yokohama, Tohoku, Hokkaido) and 60 Hertz in Western Japan (including Nagoya, Osaka, Kyoto, Hiroshima, Shikoku, Kyushu), however this frequency difference affects only sensitive equipment such as old CRT Televisions. Watch this document for some other informations: http://www.kepco.co.jp/english/guide/pdf/2.pdf

Before start your travel, check every power supply of your devices (the ones that you have to bring with you in the travel) to find if japanese voltages and frequencies are supported.

For plugs is important to buy an adapter like this (usually sold in ebay for example, searching Universal Travel Adaptor Plug):