South Korea, with an estimated 2020 population of 51,780,5798 million, has had 9,976 cases of coronavirus (as of 10:00:04 AM). They have tested more than 300,000 people and have had 169 deaths. Of those 9,976 cases, 5,828 are reported as recovered leaving them with 3,979 active cases. Outside of China, there are currently twelve countries with more cases than South Korea. They are United States (population 330 million), Italy ( 60 million), Spain (47 million), Germany (83 million), France, (67 million), Iran (83 million), United Kingdom (66 million), Switzerland, (9 million), Turkey (83 million), Netherlands (17 million) and Austria (9 million). Of those twelve countries, only Austria was less deaths than South Korea (although not per capita). There are an additional five countries with more deaths than South Korea (Belgium, Sweden, Brazil, Portugal and Indonesia). It is clear that South Korea has done a better job at containing the virus than at least 17 other countries.
This appears to be the case for many of the countries bordering China. Japan has 2,384 cases and 57 deaths (population 126 million), Taiwan has 339 cases and 5 deaths (population 23 million), and Vietnam has 227 cases and no reported deaths (population 96 million). Japan, South Korea and Taiwan are three of the five major trading partners of China (the others being the United States and the European Union). They are the closest to the source of the disease, were among the earliest to catch it, and yet they have certainly mitigated the results of the disease, and might even yet contain it. All three countries are democracies. Many other countries have had a longer warning period and do not seem to have done as well at containing the virus.
Is the difference leadership? Is the difference the responsive of the government and their health care system? What has South Korea, Japan, Taiwan and Vietnam done that the United States, Italy, Spain, Iran and so forth have not done?