Korean stocks erased their gains for the year this week and are trading at their cheapest level in around a decade on some metrics. Unfortunately for bargain-hunters, they are cheap for a series of very good reasons.

Few countries are as exposed to international trade winds as South Korea. The East Asian nation currently finds itself under threat from a slowdown in the global semiconductor industry, a sea change in trans-Pacific trading relations, and falling global trade volumes. This has left the country’s listed companies...