Yuriko Koike, governor of Tokyo and leader of the Party of Hope, speaks at a campaign rally in Tokyo on Tuesday. (Bloomberg/Bloomberg)

Japanese political leaders focused on the economy as campaigning for this month's snap election began Tuesday, with Prime Minister Shinzo Abe urging voters to give him more time to work on the recovery while a new rival party vowed to scrap a planned consumption tax increase.

But the Oct. 22 election is shaping up to be much less of a competition than many had hoped — or feared — as Yuriko Koike, head of the new party and the populist governor of Tokyo, decided against running for parliament, effectively taking herself out of the race to become prime minister. 

Koike, a former defense minister in Abe's government, started the Party of Hope last month specifically to compete against the ruling Liberal Democratic Party, although there are few policy differences between them.  

"It's a politician's job to give people hope and dreams. We will restore people's trust in politics," Koike told potential voters outside a Tokyo train station Tuesday. She urged voters to help her party end "Abe-dominant politics."

Even as campaigning began Tuesday, some analysts thought Koike would still throw her hat in the ring as a candidate for parliament before the 5 p.m. deadline. 

But she did not, instead urging voters to back her party even without her. The hastily formed Party of Hope, which incorporates some lawmakers from the flailing opposition Democratic Party, now appears leaderless, without an obvious candidate for prime minister.

A poll by public broadcaster NHK published Tuesday offered a devastating prognosis for Koike's party, putting support for it at 4.8 percent, compared with 31.2 percent for Abe's LDP.

Koike's decision not to run for parliament as the leader of her party shows that it "appears to be less a nascent second major party and more a vehicle for a Koike vendetta against Abe," said Tobias Harris, an analyst at Teneo Intelligence, a consultancy. 

Abe, for his part, started campaigning in Fukushima, the prefecture that was the site of the 2011 nuclear disaster, where he said he was not interested in "political fads or slogans."

"In this election, we will promote our policies honestly and earnestly," he said, vowing to press ahead with a planned increase in the consumption tax from 8 percent to 10 percent but promising to use the money for child care and education.

Abe, who has been in power for almost five years, dissolved the lower house of the Diet, or parliament, last month and called the snap election, 14 months ahead of schedule, to capitalize on a sudden bounce in his poll numbers. 

The conservative prime minister had seen his ratings plummet at the beginning of the summer amid corruption allegations, but North Korea's flurry of missile launches and its Sept. 3 nuclear test helped restore Abe's fortunes.

Abe said he wanted a new mandate to crack down on North Korea, a point he repeated Tuesday. "This election will determine how we should deal with the threat," he said in Fukushima. "We must continue to apply pressure."

But some analysts say the hard-line prime minister's real aim is to win a new mandate and use it to make progress on his top political goal: revising the U.S.-written postwar constitution to allow Japan to return to normal military footing after seven decades of imposed pacifism.

Although the Party of Hope had little chance of taking control of the lower house of the Diet, it had looked set to imperil Abe's two-thirds majority, which he needs to push through constitutional changes.

The most important factor now, Harris wrote in a research note, is turnout. Record-low turnout in 2012 and 2014 helped Abe win landslide victories, so Koike's party and other opposition parties will have to motivate voters if they want to thwart him.

Separately Tuesday, a district court in Fukushima ordered the Japanese government and the Tokyo Electric Power Co., the nuclear plant operator, to pay $4.4 million in damages over the 2011 triple meltdown at the Fukushima Daiichi nuclear power plant. 

The class-action suit was brought by about 3,800 plaintiffs and is the largest of about 30 suits filed against the authorities after the disaster, which was triggered by a huge earthquake and tsunami that overwhelmed the plant.