Their epidemic hit about one month sooner than ours did. Countries have had a Gaussian curve bell graph of cases and theirs peaked and came back down in similar fashion to other countries whose case load spiked earlier.
The US is about a month behind.
You have to scroll down about 1/3 of the page on the S. Korea site to see their graph of Daily New Cases, and about 1/2 down the page for the US graph.
Daily New Cases in South Korea
https://www.worldometers.info/coronavirus/country/south-korea/
Daily New Cases in the United States
https://www.worldometers.info/coronavirus/country/us/