Factors speculated to explain this include the government response, a milder strain of the virus, cultural habits such as bowing etiquette and wearing face masks, handwashing with sanitizing equipment, a protective genetic trait, and a relative immunity conferred by the mandatory BCG tuberculosis vaccine.

[6][7][27][28] The National Institute of Infectious Diseases (NIID) of Japan has determined from its genetic research that the COVID-19 variant of the first wave is derived from the Wuhan type that is prevalent in patients from China and other countries in East Asia.

[33] On 1 February 2020, the Japanese government enacted restrictions to deny entry to foreign citizens who had visited Hubei Province within 14 days and to those with a Chinese passport issued from there.

[40] On 6 February 2020, Abe invoked the Immigration Control and Refugee Act to deny entry to the cruise ship MS Westerdam from Hong Kong after one of its passengers tested positive for COVID-19.

[41] After the COVID-19 outbreak on the cruise ship Diamond Princess, the Japanese government shifted its focus from a policy of containment to one of prevention and treatment because it anticipated increasing community spread within Japan.

As few mainstream medical facilities in Japan can conduct PCR tests, Abe also promised to increase the number of institutions with such kits, including universities and private companies.

The Ministry of Health, Labour, and Welfare worked with local governments to establish 536 consultation centers that covered every prefecture within the country to provide citizens with instructions on how to receive COVID-19 testing and treatment.

[47][48] On 16 February 2020, Abe convened the government's first Novel Coronavirus Expert Meeting (新型コロナウイルス感染症対策専門家会議) at the Prime Minister's Office to draft national guidelines for COVID-19 testing and treatment.

[49] The meeting was chaired by Wakita Takaji [ja], Director of the NIID, who brought together ten public health experts and medical professionals from across Japan to coordinate a response to the virus with Abe and the government's coronavirus task force in a roundtable format.

[57] During the meeting, the medical establishment presented its policy recommendations in the form of a views report (新型コロナウイルス感染症対策の基本方針の具体化に向けた見解), concluding that the most important objective must be the prevention of large-scale disease clusters and a decrease in outbreaks and deaths.

[60] After a spike of infections in Italy, Iran, and South Korea, Abe decided that the government's disease countermeasures would prioritize the prevention of large-scale clusters in Japan.

This included controversial requests to suspend large-scale gatherings such as community events and school operations, as well as to limit patients with light cold symptoms from visiting medical facilities to prevent them from overwhelming hospital resources.

The policy also recommended that people at a higher risk of infection – including the elderly and patients with pre-existing conditions – avoid hospital visits for non-treatment purposes, such as by ordering prescriptions over the telephone instead of in person.

The panel of medical experts concluded that Japan was currently not on track to experience a large-scale cluster, but stated that there was a two-week time lag in analyzing COVID-19 trends and that the country would continue to see more infections.

[66] On 5 February 2020, the Abe administration's coronavirus task force initiated a political debate on the introduction of emergency measures to combat the COVID-19 outbreak a day after the British cruise ship Diamond Princess was asked to quarantine.

After lawmakers representing almost all of the major political parties – including the Jimintō, Rikken-minshutō, and Kokumin-minshutō – voiced their strong opposition towards this proposal and asserted that the Constitution allowed for emergency measures, the Abe administration moved forward with legislative reform instead.

During such a period, governors of affected areas will receive the following powers: (1) to instruct residents to avoid unnecessary outings unless they are workers in such essential services like health care and public transportation; (2) to restrict the use or request the temporary closure of businesses and facilities, including schools, social welfare facilities, theatres, music venues, and sports stadiums; (3) to expropriate private land and buildings to erect new hospitals; and (4) to requisition medical supplies and food from companies that refuse to sell them, punish those that hoard or do not comply, and force firms to help transport emergency goods.

[4] In response to the statement, Abe instructed Economic Policy Minister Yasutoshi Nishimura to establish a special government task force to combat the spread of the virus.

[4] On 2 April 2020, the Ministry of Health issued a notice that urged non-critical COVID-19 patients to move out of hospitals and stay at home or facilities designated by local governments.

[77] Prefectural governors across the country began arranging accommodation for such patients through hotel operators and dormitories and issued official requests to the Japan Self-Defense Force for transportation services.

[92] He also declared that his Cabinet would set aside 15.3 billion yen from contingency funds to facilitate the donation of isolated virus samples to relevant research institutions across the globe.

[113] The strict constraints on testing for the virus by Japanese health authorities drew accusations from critics such as Masahiro Kami that Abe wanted to "downplay the number of infections or patients because of the upcoming Olympics."

It was reported that only a few public health facilities were authorized to test for the virus, after which the results could only be processed by five government-approved companies, which created a bottleneck forcing clinics to turn away even patients with high fevers.

[138] On 25 February 2020, the Ministry of Health, Labour and Welfare established the Cluster Response Team (クラスター対策班) in accordance with the Basic Policies for Novel Coronavirus Disease Control.

[143] During times when the number of infected patients rises to such an extent that individual contract tracing alone cannot contain a COVID-19 outbreak, the government will request the broad closure of such high-risk businesses.

[53][52] The country's high number of computed tomography (CT) scanners (111.49 per million people) allows them to confirm suspicious pneumonia cases and begin treatment before testing them for COVID-19.

Since the government cannot enact compulsory measures to enforce these requests, it has instead embarked on a social engineering program to train its citizens to comply with them on a voluntary basis during current and future state of emergencies.

[142] To reduce person-to-person contact, the government has instructed the public to refrain from going to high-risk environments (the Three Cs: closed spaces, crowded places, and close-contact settings) and events involving movement between different areas of the country.

Nippon Professional Baseball's preseason games and the Haru Basho sumo tournament in Osaka were to be held behind closed doors, while the J.League football and Top League rugby suspended or postponed play entirely.

[200][201] Beginning in March 2020, many Japanese animated films and TV shows announced changes or postponed broadcasts due to production problems resulting from a shortage of outsourced staff.