Of the 169 new cases confirmed in Japan on Sunday, 68 were in Tokyo. This is the largest single-day increase reported by any prefecture so far. Health authorities say they have been unable to trace the routes of infection in about 40 percent of these cases. The total number of infections in Tokyo now stands at 430.
Last Wednesday, governor Koike Yuriko asked people in the capital to stay home over the weekend, refraining from all but essential travel.
Only a few people were out in normally crowded areas like the Shibuya scramble crossing. Shinjuku's Kabukicho entertainment district was nearly deserted on Saturday night, as most movie theaters and karaoke parlors were closed.
On Sunday, a low pressure system and a cold air mass brought a bit of rare unseasonal snow to the capital. The weather may have convinced people to follow the governor's request and stay at home.
Officials warn that Tokyo is now at a critical juncture to prevent what is known as an epidemiological overshoot, a situation in which there is an explosive increase in the number of cases.
The Metropolitan Government plans to continue to ask residents to work from home and refrain from nighttime outings. The request will remain in place until at least April 12.
Similar measures were in place across the country this weekend. Prefectural governors in Osaka and Fukuoka were among those urging people to stay inside unless absolutely necessary.
Speaking to the media on Saturday, Prime Minister Abe Shinzo warned that the country needs to brace itself for a prolonged battle against the virus.
"We can estimate from the examples in the US and Europe that the number of cases could jump more than 30 times in just two weeks," Abe said. "We must fight against the terrifying enemy with dauntless resolve."
He added that government officials will work with local authorities to curb the outbreak.
At a time of year when people are usually celebrating cherry blossom season, Japan is increasingly gripped by a sense of crisis.