|The hole in Plug is not required for Korean Wall outlet|
Since of it, if you travel to Korea, you would better to provide plug adapters for your mobile or laptop power supply, just same like to be applied Germany.
The mostly known as "Type F" plug have two round pins, diameter 4.8mm and spaced 19mm. There shown a hole in the plug of the photo but the hole for ground connection is not required (some European countries are using) for Korean wall outlets and the ground connection is made through the pins, shown up & down, of wall outlet and terminals on the plug surface.
Another type of plug is accepted for the Korean wall outlets which has no ground connection, mostly used for double insulated electric appliances. The plug shape is identical with "Type C" but the pin diameter is not 4.0mm of "Type C" but 4.8mm (same as "Type F").
Please be aware the "Type C" plug looks like to fit "Type F" wall outlet but "Type C"(4.0mm dia.) plug makes loose fitting with "Type F" what means a bad electric contact and the bad contact could make unstable contact with sockets and could yield another problem. It would be very dangerous too.
I found a website with wrong information, showing the applicable plug types in Korea as "Type C" and "Type F".
I had made an advise to show just "Type F" only and they have corrected the information(refer to this link).
|"Type C" plug have two 4.0mm of pins but no good contact with "Type F" socket.|