You Do Need power plug adapter while traveling from South Korea to Liechtenstein.

Here is Why You Need An Adapter

The outlet and plug type used in Liechtenstein are C and J and in South Korea is F. This is how they look like.

South Korea

In South Korea, outlets of type F are in use.

Type F

Liechtenstein

In Liechtenstein, outlets of type C and J are in use.

Type C

Type J