Sixteen people want to occupy Room 200 at City Hall, which is the most crowded field in memory. Almost all are considered viable contenders.
In alphabetical order they are: Public Defender Jeff Adachi, former Supervisor Michela Alioto-Pier, Supervisor John Avalos, Board President David Chiu, former Supervisor Bevan Dufty, former Supervisor Tony Hall, City Attorney Dennis Herrera, current Interim Mayor Ed Lee, venture capitalist and entrepreneur Joanna Rees, assessor-recorder Phil Ting, and St. Sen. Leland Yee.
The mayor will be chosen through the ranked choice voting system approved by voters back in 2002. It's been used in other city elections, like last year's supervisor races, but this is the first time the method will be used for a competitive mayor's race.
This method allows voters to mark their ballot with up to three mayoral choices, in order of preference. On election night the counting begins with all first choice selections. If there is a front runner who captures more than 50 percent of the vote, the race is over.
If no one gets that majority, the candidate with the fewest first choice rankings is eliminated. If that person was your top selection, you get another chance because your vote is now transferred to your second choice and all the votes are recounted. This process of eliminating last place candidates and redistributing the votes continues until someone has a winning majority and becomes the new mayor.
"I think it's a good thing because it saves money and it allows one election to determine the outcome," said Adachi.
"There's a lot of education that still has to happen," said Rees.
"I hear it all the time when I'm at house parties, from folks from the right, on the left, the middle, that they're confused, a little scared about it," said Herrera.
Some research has been done on ranked choice voting in previous city elections by USF political science professor Corey Cook.
"In San Francisco normally, more than half of the voters only list one person. And the question then becomes do voters really understand the voting system? Do they know they can put second and third choices?" said Cook.
Cook says nearly 80 percent of the voters in last year's mayor's race in Oakland marked all three choices; it was the first time ranked choice was used there. Don Perata was 11 points ahead in the first round of voting, but Jean Quan captured more 2nd and 3rd place votes, leading to her surprising win.
"I know people today, here, people will come up and say 'What happened?'" said Perata.
Perata says he accepts his defeat, but says voters, including himself, are confused about the new voting system.
"If you can't explain how on the 9th count, you lose. If I don't understand it, how could a voter understand it," said Perata.
Cook believes the ranked choice system worked in Oakland, but for the doubters, San Francisco is now a crucial test.
"The San Francisco election is a big case because people are now really aware of ranked choice voting in a way they weren't," said Cook.
If Supervisor Sean Elsbernd has his way voters won't become too familiar with it. On Election Day he plans to submit a proposal for the June ballot to repeal ranked choice voting.
"Whoever is our next mayor will be elected with less than a majority of the vote. This is an undemocratic system," said Elsbernd.
But there are many supporters.
"I love it. Well, see what the voters think," said Dufty.