Ichiro Ozawa, former leader of the Democratic Party of Japan and party defector, sent Yukiko Miyake to Chiba's fourth district to challenge Japanese Prime Minister Yoshihiko Noda for a seat in the Dec 16 House of Representatives election.

If Miyake beats Noda, he will become the first Japanese prime minister who is not a lawmaker.

It is a tough job for Miyake. Noda has represented Chiba's fourth district since 2000. He initially lost the seat in 1996 as a candidate for the New Frontier Party when Liberal Democratic Party candidate Shoichi Tanaka won by 105 votes.

Noda's chances of winning have not collapsed, but the race for Japan's premiership looks far more open than it did earlier.

Pundits expect neither the DPJ nor the LDP to secure a majority in the election.

A Jiji Press survey on Saturday found that after an accelerated realignment, 12 parties will field 1,412 candidates to run for the lower house. The 480-member house is made up of 300 single constituencies and 180 proportionally apportioned seats.

The DPJ had 233 seats and the LDP 118 when Noda dissolved the chamber ― which is more important than the House of Councilors ― on Nov 16.

The ruling DPJ has picked up the gauntlet from Japan's biggest opposition party, the LDP, and the so-called third-force parties that aim to rival the top two.

The rat race is on, though the absence of several heavyweight politicians such as former prime ministers Yukio Hatoyama, Yoshiro Mori, Tsutomu Hata and Yasuo Fukuda may make the election look very modest.

The DPJ, which had around 308 seats in the lower house when Noda assumed office in September 2011, will head into the election with the ruling bloc having effectively lost its majority in the chamber. Ninety-three DPJ members have defected to other parties or resigned to save their own political skins.

Noda, the DPJ's third premier in three years, sparked an internal split by pushing through an unpopular bill that will double the 5 percent sales tax to cope with record debt and rising welfare costs in an economy that contracted last quarter. His interest in placing Japan in the Trans-Pacific Partnership multilateral trade framework talks also caused some flights from the DPJ.

An Asahi Shimbun poll released on Monday showed that 15 percent of voters would cast their ballots for this party.

"In the election campaign that will be starting tomorrow, I'm determined to do my utmost and fight to the bitter end ... so that the Democratic Party can stay in power," Noda told reporters on Monday.

LDP leader Shinzo Abe, aiming to make a comeback as Japan's prime minister, vowed to wage a "historic battle". In an interview with the Jiji Press, LDP Executive Acting Secretary-General Yoshihide Suga said his party hopes to secure an overwhelming majority in the lower house with its partner, New Komeito, in the election.

Abe's policy platform has sparked resistance within the Komeito party, whose coalition with the LDP has lasted more than a decade in and out of government. Compromise is needed to keep the partnership alive. The LDP is continuing to take the lead in the Asahi newspaper's poll, with an approval rate of 20 percent.

The public's discontent against conventional parties has soared after a prolonged period of political paralysis. As a result, various new parties have been emerging and merging in the political arena, in a rather haphazard way. However, their abilities to take the helm of the nation are questionable. Their policies have a strong flavor of pandering to the public.

The Japan Restoration Party will field 142 candidates in the lower house election, considerably less than had been expected. The party's deputy and Osaka Mayor Toru Hashimoto said the election will be the first big test of his new party, and his party's candidates will be at the vanguard to bring about fundamental political change in Japan, TV Asahi reported. The party came in third in the opinion poll.

Political groups against nuclear energy, such as the one headed by Ozawa and the newly formed Japan Future Party headed by Shiga Govenor Yukiko Kada, agreed to join together to become a major player of the "third force".