A little over a month ago, health experts were saying Japan risked becoming one of the world’s coronavirus “disaster zones”.

Its government was already facing criticism over its decision to quarantine passengers and crew aboard the Diamond Princess cruise liner, and had been accused of underplaying the Covid-19 threat while it clung to the increasingly faint hope of hosting the Olympics this summer.

Japan was testing too few people, critics said, opting instead to focus on clusters of cases rather than overburden its healthcare system with patients displaying no or only mild symptoms who, by law, had to be admitted to hospital. One of the world’s richest countries, they said, was bungling its response.

But today, Japan can make a strong case for being another coronavirus success story, albeit one that has failed to resonate globally in the same way as those in South Korea, Hong Kong and Taiwan.

So far, Japan – a country of 126 million people with one of the biggest elderly populations in the world – has confirmed 16,433 infections and 784 deaths, out of a global death toll of more than 300,000 people.

In Tokyo, where almost 14 million people live, new cases have remained below 40 for more than a fortnight, with just five cases reported on two consecutive days this week. That compares with a peak of 206 new cases reported on 17 April. On Friday, the public broadcaster NHK reported just three new cases in the capital in the previous 24 hours.

Achieving such low figures barely seemed possible in early April when, just as the number of cases began to rise sharply in Tokyo and other major cities, neighbouring South Korea – with its widely praised regime of testing, tracing and treating – was flattening the curve.

On 7 April, the prime minister, Shinzo Abe, belatedly declared a state of emergency in the capital and other affected areas that was later expanded to include all 47 of the country’s prefectures.

But Japan’s version of “lockdown” – requests to avoid unnecessary outings, work from home and observe social distancing – came across as a timid response to a situation that risked spiraling out of control. The dispatch of two reusable masks to every household was met with derision, as people posted photographs on social media of the small, and in some cases dirty, “Abenomasks” – a play on the leader’s economic policy dubbed “Abenomics”.

Abe’s performance throughout the crisis has been uneven, according to Tobias Harris, an expert on Japanese politics at Teneo consultancy. “I think he has struggled to stay ahead of events since the beginning, has not communicated effectively, and has been poorly served by his lieutenants.”

Japan has skirted a coronavirus surge with room to spare, after new cases slowed markedly when Abe, who does not have the legal powers to declare a European-style lockdown, called on people to beat the virus by avoiding the “three Cs”: confined and crowded spaces, and close human contact.

The Abe administration has gained few political dividends for its response; instead, most plaudits have gone to the quiet determination shown by the public, armed with virus-challenging habits formed long before the pandemic.

Masks are a common sight during the winter flu season, and in spring among people with hay fever. The custom of bowing rather than shaking hands or hugging, generally high standards of personal hygiene, and the removal of shoes when entering homes have all been held up as possible explanations for Japan’s low infection rate.

Experts have pointed to universal healthcare, low obesity rates and expertise in treating pneumonia. More fanciful theories have gained traction – the consumption of foods, such as natto, that boost the immune system and, according to an unscientific experiment conducted by a TV network, the relatively low number of airborne droplets generated by spoken Japanese.

“I don’t think the falling number of infections is due to government policies,” said Ryuji Koike, the assistant director of Tokyo Medical and Dental university hospital. “I think it looks like Japan is doing well thanks to things that can’t be measured, like daily habits and ‘Japanese behaviour’.”

Personal habits and cultural traits, however, tell only part of the story. While Japan hesitated before imposing restrictions on overseas visitors, it was quick to recognise the dangers of mass gatherings.

Museums, theatres, theme parks and other attractions have been closed for months. Japan’s professional football league suspended matches three weeks before 150,000 people attended the four-day Cheltenham horse racing festival in Britain.

Rugby and baseball leagues followed suit, delaying the start of their seasons, while sumo authorities decided to hold the recent spring tournament without spectators for the first time in the sport’s history. Abe was criticised for calling for “unnecessary” school closures in early March, yet many other countries then did the same.

Rob Fahey, a research associate at the Waseda Institute of Political Economy in Tokyo, believes declaring Japan’s ability to contain the outbreak a “mystery” ignores the role of individual and collective action.

“Acknowledging this, however, requires looking beyond the usual set of policy actors and recognising that Japan’s response overall can still have been exemplary even if the performance of its central government left much to be desired,” Fahey wrote in the Tokyo Review this week.

Japan’s incremental exit from the state of emergency continues. Last week, Abe ended the measure in 39 prefectures, adding another three this week. Tokyo and four other prefectures could join them as early as Monday, according to media reports.

But experts are warning against complacency given that the low rates of testing may be distorting the extent of infections – a hazard recognised by the government’s own expert, Shigeru Omi, who admitted that nobody knows whether the true number of coronavirus cases “could be 10 times, 12 times or 20 times more than reported”.

As Tokyo’s backstreet bars and restaurants started filling up again this week – with some staying open beyond the 8pm closing time requested by the city’s governor – Abe sought to balance cautious optimism with a dose of post-pandemic reality.

The weeks ahead would not mark a return to the days before the outbreak, he said, but the “beginning of a challenge to create a ‘new normal’”.

Agence France-Presse contributed to this report