Yuriko Koike’s win fends off challenges from dozens of candidates vying to unseat the ruling party-backed incumbent.

Tokyo Governor Yuriko Koike has declared victory after exit polls projected her winning a third four-year term as head of Japan’s influential capital.

With about 40 percent of the votes counted, Koike, 71, on Sunday led by more than 1.29 million votes, twice as many as her top rivals Shinji Ishimaru and Renho Saito, who had 664,000 and 603,000 votes, respectively.

Official results are expected early on Monday.

The vote was also seen as a test for Prime Minister Fumio Kishida’s governing party, which supports Koike, the first woman to lead the Tokyo city government.

Tokyo, a city of 13.5 million people with outsized political and cultural power and a budget equaling some nations, is one of Japan’s most influential political posts.

A record 55 candidates challenged Koike, and one of the top contenders was also a woman – liberal-leaning former lawmaker Saito, who usually uses only her first name, Renho, and who was backed by opposition parties.

Minutes after exit polls projecting her victory, Koike showed up at her campaign headquarters in Tokyo and celebrated by thanking the voters who chose her.

“I believe the voters gave me a mandate for my accomplishment in the past eight years,” Koike said. She pledged to push for more reforms and support for Tokyo residents.

“I am fully aware of my heavy responsibility,” she said. “I will tackle my third term with all my body and soul.”

Koike and her major rivals have particularly pledged to improve low birth rate issues by expanding support for parenting, with Koike promising subsidised epidurals.

“After having their first child, I hear people say they don’t want to experience that pain again,” Koike said during the election campaign, according to local media.

“I want people to see childbirth and raising children as a happiness, not a risk,” she said.

A victory for Koike could help embattled Kishida resist calls from within the ruling Liberal Democratic Party (LDP) to step down as the popularity of his group declines.

The LDP in April lost three parliamentary by-elections to the opposition Constitutional Democratic Party of Japan (CDPJ) as well as the vote for the governorship of nearby Shizuoka prefecture, which was won by Yasutomo Suzuki, a candidate backed by the opposition group.

Moreover, Japan has never had a woman prime minister and a large majority of lawmakers are men, although Tokyo accounts for a 10th of the national population and a fifth of the economy.