Former Defense Minister Yuriko Koike is gaining the upper hand in the race for Tokyo governor, followed by former internal affairs minister Hiroya Masuda and veteran journalist Shuntaro Torigoe, a Kyodo News survey has shown.

Still, the potential for a tight race remains high ahead of next Sunday’s election, with 31.1 percent of respondents saying they had yet to decide who to vote for, the telephone survey conducted Saturday and Sunday showed.

Koike has the support of nearly 35 percent of unaffiliated voters and some ruling Liberal Democratic Party backers, although the 64-year-old former Lower House member is running without the party’s blessing.

She also received backing from some supporters of the main opposition Democratic Party, the survey showed. And in a surprising development, she also received support from some backers of the Japanese Communist Party (JCP). According to the survey, Koike proved most popular among voters under 60 years old.

Masuda, 64, a former Iwate governor running with the backing of the LDP and junior coalition partner Komeito, attracted nearly 40 percent of LDP supporters — up from some 30 percent in the previous poll a week ago — and more than 60 percent of the Komeito supporters.

Torigoe, the opposition block’s joint candidate, was backed by nearly 60 percent of the Democratic Party and JCP supporters, unchanged from the previous survey.

The 76-year-old former TV anchorman also saw his support among nonaffiliated voters, especially female voters, decline, the latest survey indicated. It showed he was most popular among voters 60 and older.

In answering a multiple response question regarding where the new governor’s priorities should lie, 42.1 percent of respondents said education and child-rearing support was most important. This was followed by 38.7 percent who cited medical and nursing care and 28.1 percent who said administrative reform was tops.

Preparations for the 2020 Tokyo Olympic and Paralympic Games was considered a top priority by 11.6 percent, according to the survey.

The telephone survey covering 1,528 randomly selected households with eligible voters in Tokyo. Valid responses were received from 1,026 people.

Swing voters are likely to prove key in the race, with so many having yet to decide. Tokyo is believed to have a large number such voters, who are not loyal to any particular party.

“If independent voters don’t go to the polls, that will mean death for me,” Koike told a crowd during a stump speech Saturday.

Koike’s campaign team has also taken to social media, including Facebook and Twitter, to make her pitch to voters. On Saturday, more than 20 photos and videos were posted to her Twitter account while her Facebook updates were also frequent.

For Masuda, winning over swing voters could prove a challenge. Despite serving in the Cabinet as internal affairs minister and winning three gubernatorial terms in Iwate, his camp is well aware of the uphill battle he is facing.

“I don’t think we can count on swing voters,” one Masuda campaign staffer said.

Another Masuda staffer voiced concern over the split within the LDP.

“When we went to one of our supporters to seek backing for Masuda, they said ‘You’re talking about Koike, right?’ Many believe that Koike is the LDP-endorsed candidate. Masuda is not well known,” the staffer said.

Torigoe’s campaign team is also setting its sights on winning over swing voters.

“We will seek support from swing voters in the last week of the campaigning,” DP Secretary-General Yukio Edano told reporters Friday

In a bid to avoid alienating the key voting group, Edano said that Torigoe’s campaign would no longer focus on emphasizing the opposition parties’ support.

Torigoe has so far eschewed stump speeches on the campaign trail, instead preferring to participate mainly in gatherings of liberal-minded citizens groups, where he has lambasted the administration of Prime Minister Shinzo Abe.