His approval rating has nosedived to an all-time low of 31.8% over his government’s pandemic response
Japan's Prime Minister Yoshihide Suga said on Friday he will not run in his ruling party's upcoming leadership vote, throwing open the race for the next premier of the world's third largest economy.
The shock decision after just a year in office comes with Suga's approval ratings at an all-time low over his government's pandemic response.
And it suggests a possible return to political turbulence for Japan, which regularly cycled through prime ministers before the lengthy tenure of Suga's predecessor Shinzo Abe.
"In one year since I became prime minister, I have poured all of my strength into dealing with the various problems facing the country, with anti-coronavirus measures at the forefront," Suga told reporters.
He said he realised that running for election and handling virus policies would require "enormous energy."
"I came to the realization that I cannot do both. I had to choose one of them," he added.
Liberal Democratic Party (LDP) secretary general Toshihiro Nikai said he was "surprised" by Suga's decision not to stand in the September 29 leadership race.
"It's truly regrettable. He did his best," Nikai said.
Suga had dropped no hints of his plans to leave office before contesting his first general election, having replaced Abe who resigned for health reasons.
He had been widely expected to seek re-election as LDP leader, with most speculation surrounding only how soon after that he would call a general election.
The election must be called by late October and held by the following month. The LDP is expected to remain in power, though some members feared losing seats due to Suga's unpopularity.
His government's approval rating has nosedived to an all-time low of 31.8%, according to a poll by Kyodo news agency last month.
Suga's announcement cheered investors, whose hopes that a new leader could announce a stimulus package pushed the benchmark Nikkei index up more than two percent at the close.
The decision was also likely to be privately welcomed by some in the party, said Tomoaki Iwai, a professor of politics at Nihon University.
"For the LDP MPs it's a relief that they don't have to run in general elections under an unpopular prime minister," he told AFP.
Japan has recorded nearly 16,000 Covid-19 deaths overall and is struggling through a record fifth wave of cases, after a slow start to its vaccine rollout.
Much of the country is currently under virus restrictions targeting evening entertainment, and the measures have been in place in some areas for almost the entire year.
But they were unable to stop the latest surge driven by the more contagious Delta variant, even as vaccination has picked up pace with more than 47% of the population fully inoculated.
The 72-year-old Suga's rise to prime minister last year capped a lengthy political career.
He previously served in the prominent role of chief cabinet secretary, and he had earned a fearsome reputation for wielding his power to control Japan's sprawling and powerful bureaucracy.
The son of a strawberry farmer and a schoolteacher, Suga was raised in rural Akita in northern Japan and put himself through college by working at a factory.
He was elected to his first office in 1987 as a municipal assembly member in Yokohama outside Tokyo, and entered parliament in 1996.
The leadership race was already starting to heat up on Friday, with local media reporting that former defence minister Taro Kono, who manages Japan's vaccine rollout, would stand for election.
LDP policy chief Hakubun Shimomura, divisive right-winger Sanae Takaichi and popular ex-defence minister Shigeru Ishiba are also considered possible candidates.
But the only politician to officially announce his plans so far is Fumio Kishida, who has pledged to spend big if he wins.
Iwai said the former foreign minister would now be in with a good chance.
"Kishida is probably the front runner, as he is moderate and capable," Iwai said.
The turmoil makes it likely the election will be pushed back as late as possible, into November, he added.