Does Japan need an adapter?

Is needed. The voltage used in Japan is also very different from that in China. They use 100 volts, while ours is 250 volts ... so the high-power electrical appliances used in China, such as hair dryers and electric irons, need to be equipped with a transformer.

The socket panel in Japan is six holes 15A, with three holes on the top and three holes on the bottom. Two three-pin plugs can be inserted at the same time. Two ungrounded pins can also be inserted at the same time. Two-pin and three-pin plugs are "flat and vertical" and can be used universally. The domestic two-pin plug is "vertical", while the two metal pieces outside the three-pin plug ground wire are "inclined". Therefore, the domestic two-pin plug cannot be inserted into the three hole socket panel.

In Japan, two-hole plugs and three-hole plugs have the same shape and size and can be used universally. Including air conditioning sockets, you can also use ordinary plugs, which has good compatibility. At present, there are five-hole 10A sockets in China, and two plugs can be plugged in at the same time. Can this explain that the ordinary standard five-hole socket is a design failure?

Ok, I see the difference between China and Japanese outlets. When traveling to Japan, if it is a three-hole plug, remember to bring a universal GSM travel adapter.