South Korea took countermeasures to entry restrictions that Japan placed on travelers from here after a surge in novel coronavirus cases.

Japan, on Thursday. imposed a two-week quarantine on all visitors from Korea. It also revoked some visas and suspended the visa-waiver program.

The next day, Seoul announced it will end visa-free entry for Japanese citizens and suspended the validity of visas already issued.

Though the measures taken by Tokyo apply to travelers not only from Korea but also China till the end of this month, it is regrettable that Japan effectively barred entry without any prior notice to or consultation with Seoul.Korea and Japan are in close proximity, and human exchanges are heavy. They should have sought reasonable and efficient ways to contain the spread of the virus together, but there were no such efforts.

Japan’s response to the virus was problematic from the beginning. Like Korea, Japan did not restrict entry from the whole of China, either, even as the number of confirmed coronavirus infections in Japan rose past 1,000, including cases on a cruise ship.

The Japanese people were disappointed at Prime Minister Shinzo Abe’s response to the COVID-19 outbreak and are worried about the possible postponement of the Tokyo Summer Olympic Games slated for July. Abe may have needed to turn public opinion in his favor.

Japan’s announcement of its latest steps came shortly after Chinese President Xi Jinping’s state visit to Japan was postponed. This raises speculation that Japan held back from barring entry from China as a whole out of political considerations for Xi’s visit.

Abe may have sought to boost his popularity by stimulating anti-Korean sentiment as well as taking steps to stem the influx of infection sources. This may be the reason why it took measures without prior notice.

On the other hand, Japan’s abrupt measures raise concerns about Korea’s diplomacy toward Japan. Given a surge of confirmed infections in Korea, a looming possibility of the delay of the Olympics and an increase in the number of countries that restrict entry from Korea, it was not difficult to expect Japan to take similar restrictions on entry sooner or later. The government under President Moon Jae-in needs to review whether it has alienated Japan diplomatically.

More than 100 countries restrict the entry of all travelers from Korea. Out of its top 10 export markets, nine except the US limit entry from Korea. They took such steps as Korea has the second-largest number of confirmed infections in the world.

Some provincial governments of China began to quarantine travelers from Korea shortly after it raised the virus crisis alert to the highest level. The quarantine was forced without prior notice or consultation. Beijing says it has little to do with the measures, saying that is implemented by provincial authorities, not by the central government. The Moon administration did not take reciprocal measures.

It did not take countermeasures, either, to other countries that limit the entry of visitors from Korea. It hit back only against Japan. Korea would find it hard to refute criticisms that its countermeasures lack equity.

Probably more serious is the fact that the US, Korea’s key ally and superpower, has been escalating its response to the spread of the coronavirus.

The US State Department raised the travel advisory for Daegu to Level 4 late last month, warning its citizens to “not travel” to the southeastern city of Korea.

If Washington bars entry to travelers from Korea, other countries will likely follow suit. US-Korea trade will shrink, putting the do0mestic economy in a big crunch.

Korea countered Japan’s effective entry ban with reciprocal measures, but an emotional battle or extreme confrontation will be only detrimental to both sides.

The fundamental solution is to contain the diffusion of COVID-19 outbreak as quickly as possible.

But while Japan began to restrict the entry of visitors from China, Korea still kept its doors open to China except for Hubei. Some say it is meaningless, and too late, as Japan did now because the number of confirmed infections has already topped 7,000. Concerns about being isolated have not abated. Something went wrong from the start.