The Olympic torch relay set off from Fukushima on Thursday, beginning a four-month countdown to the summer Games in Tokyo, delayed from 2020 and the first ever organised during a global pandemic.
Casting a pall over celebrations, North Korea launched two short-range ballistic missiles before the relay began.
About 10,000 runners will carry the torch across Japan's 47 prefectures and far-flung islands, starting from the site of the 2011 quake and tsunami that killed about 20,000 people and sent tens of thousands fleeing radioactive plumes.
"For the past year, as the entire world underwent a difficult period, the Olympic flame was kept alive quietly but powerfully," Tokyo 2020 president Seiko Hashimoto said at the opening ceremony, which was closed to spectators.
"The small flame did not lose hope, and just like the cherry blossom buds that are ready to bloom, it was waiting for this day," Hashimoto said.
After the North Korean missile launch, Japanese Prime Minister Yoshihide Suga assured reporters the national government was cooperating with Tokyo and the International Olympic Committee to host a secure Games.
"We will do our utmost in terms of coronavirus measures and continue to work with related areas to contain the spread of infections and hope to work towards a safe and secure Games," Suga said.
Japan has fared better than most countries during the pandemic, with fewer than 9,000 coronavirus deaths, but Tokyo reported 420 cases on Wednesday, the highest single-day figure this month.
The majority of the public is against the Olympics being held as scheduled, polls show.
NO CROWDS OR CHEERING
The relay, which will culminate with the Olympic opening ceremony on July 23, has been hit by several high-profile runner cancellations as celebrities and top-level athletes have pulled out, citing late notice and worries over the pandemic.
The starting ceremony was held at J-Village in Fukushima, a sports complex converted for several years into a staging ground for workers decommissioning the crippled nuclear power plant.
"For the torch relay viewing, please ensure you are wearing a mask, keep proper distance, don't stand close to each other and support with things like clapping, instead of using a loud voice," an announcer at the site said.
The brief and solemn ceremony - originally planned for thousands of fans as a celebration of Japan's recovery - was closed to the public.
It featured several low-key events, including a drum concert and dance performances by a group of residents from Fukushima, followed by a children's choir.
Members of the Japanese national women's soccer team used the Olympic flame, flown in from Greece last year, to light the torch.
The runners, some wearing masks and white uniforms decorated with red, ran out of J-Village and passed on the flame to the next runner. About a dozen staff escorted the runner, racing together and following a van guiding the relay.
"I’m convinced that, under this coronavirus pandemic, the Olympics will surely bring courage and vigour to people in east Japan, where recovery is still halfway through," Norio Sasaki, coach of the women's soccer team that won the 2011 World Cup, said after running the first leg of the relay.
Television helicopters followed the run and the number of roadside spectators, waving Olympic flags, increased as the day went on. But they were masked and kept apart.
Organisers have said that the relay will skip areas that are too crowded, or pause until people disperse.
'YOU MUST BE JOKING'
"Fukushima's recovery is going steadily," Fukushima governor Masao Uchibori said at the launch ceremony.
"But there are still many people who can't return to their homes, and many difficult issues such as reviving these areas, rebuilding the lives of their residents," he said.
The torch will travel through some of the worst-hit areas first.
Japan has spent nearly $300 billion to revive the region, but many locals are apprehensive about the Games, as areas in Fukushima remain off-limits, worries about radiation linger and many who left have settled elsewhere. Decommissioning will take up to a century and cost billions of dollars.
A protester driving a silver van near the relay shouted over a loudspeaker, questioning how the Olympics could contribute to the region's recovery.
"You must be joking," the man yelled. "Everyone knows we can't have the Olympics," he shouted.
The organisers insist the Olympics will go ahead, but doctors and nurses have complained about the strain on hospitals and experts warn about the spread of virus variants.
Adding to the challenge, Japan was the last of the Group of Seven industrialised nations to launch a vaccine drive. Only 700,000 people have been inoculated so far, most of them medical workers.
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