The race to succeed outgoing Japanese Prime Minister Shinzo Abe is intensifying, with a flurry of brokering and manoeuvring in late-night meetings among factions in the ruling Liberal Democratic Party (LDP).
At least five former Cabinet ministers have said they will vie for the top job, while three incumbent ministers said they will discuss the way forward with their colleagues.
But pundits say Chief Cabinet Secretary Yoshihide Suga, 71, trusty lieutenant to Mr Abe, is easily the front runner if he opts to run.
Mr Suga previously said he was not interested, but has high public recognition as Mr Abe's top government spokesman since Mr Abe took power in December 2012.
Still, details of the internal party poll to choose the next LDP president - including the when and the how - remain undecided and will only be fixed at the party's general council meeting on Tuesday.
Local media yesterday floated Sept 15 as a possible date for the vote to decide Mr Abe's successor.
As the LDP forms the government, the party leader also traditionally becomes prime minister.
The LDP usually announces an election for its president a month in advance.
In this scenario, lawmakers in the Diet and rank-and-file grassroots members across the nation will cast their vote but it will take time, as ballots will have to be mailed across the country.
Mr Abe's abrupt resignation on Friday due to a flare-up of a chronic condition comes a year before his term was due to expire in September next year.
This triggers the possibility of a streamlined extraordinary election, where MPs and representatives of the party's local chapters can vote.
MR YOSHIHIDE SUGA, 71
Chief Cabinet Secretary
Mr Suga previously said he was not interested, but has high public recognition as Mr Abe's top government spokesman.
MR FUMIO KISHIDA, 63
Former foreign minister
Once Mr Abe's preferred successor, but concerns have emerged about his lack of charisma and public presence.
MR SHIGERU ISHIBA, 63
Former defence minister
Regularly tops surveys as the public's preferred PM.
The LDP now has 394 lawmakers in the Diet, and as each of the 47 prefectural chapters is allotted three votes, it means Mr Abe's successor will be decided by 535 party voters.
While the LDP president carries a three-year tenure, the winner this time will carry out the remainder of Mr Abe's term, with a poll still to be set for September next year.
Mr Abe has said he will stay on as PM until his successor is chosen. The Cabinet will continue to be in charge, but will not be able to adopt new policies.
The victor will inherit a country that is more confident on the global stage, but beset by domestic problems, including mounting debt, an economy battered by the Covid-19 pandemic and a shrinking population.
He or she will have to oversee the Tokyo Olympic Games, which have been postponed to next July, and prepare for a national election to form the government, which is due in October next year.
There is no heir apparent, leaving the field wide open for what domestic media term the "post-Abe" era.
Mr Abe himself declined to name his preference, saying on Friday: "There have been a lot of promising names, and I expect that the best candidate will be chosen."
For any candidate to officially enter the fray, they will first have to secure 20 nominations among the LDP Diet members. Mr Suga does not belong to any faction, but he has plenty of clout within the LDP and the government.
Five former Cabinet ministers have announced their ambitions, including former defence minister Shigeru Ishiba, 63.
He regularly tops surveys as the public's preferred PM and has solid support among regional LDP members, but is less popular among lawmakers due to his frequent criticisms of Mr Abe.
Former foreign minister Fumio Kishida, 63, was once Mr Abe's preferred successor, but concerns have emerged about his lack of charisma and public presence to fill Mr Abe's big shoes.
Two women ministers - former internal affairs minister Seiko Noda, 59, and former defence minister Tomomi Inada, 61 - have both said they are keen to run, and would become Japan's first female prime minister in the unlikely event that either of them can gather enough party support to prevail.
Former education minister Hakubun Shimomura, 66, now the LDP election strategy committee chief, is also eyeing the top job, but is seen as a rank outsider.
Meanwhile, among the incumbent Cabinet who are keen are defence chief Taro Kono, 57, Foreign Minister Toshimitsu Motegi, 64, and Environment Minister Shinjiro Koizumi, 39.
Mr Kono, who is popular for his candid remarks and social media savvy, told reporters yesterday that he will "think hard about contesting in the election".
Likewise, Mr Motegi said he will discuss the issue with his faction colleagues, while Mr Koizumi said coyly: "The work of the prime minister is not something that can be done alone. Without the support of colleagues, I cannot get to the starting point."
Meanwhile, deputy PM and Finance Minister Taro Aso, 79, has put himself out of the running, telling a party faction meeting on Friday night that he will not contest the election.