The Democratic Party of Japan won the Lower House election by a landslide Sunday, grabbing at least 300 seats in the 480-seat chamber.

From Kyodo and Japan Times reports

The victory by the main opposition party will end more than half a century of almost uninterrupted rule by the Liberal Democratic Party. It will also usher in DPJ President Yukio Hatoyama, 62, as the new prime minister by mid-September.

As of 12:50 a.m. Monday, the DPJ-led opposition camp had secured 327 seats against just 126 for the LDP-New Komeito ruling bloc. In the opposition camp, the DPJ alone had 300 and was set to add more as more vote counts came in.

Flush with victory, DPJ executives started full-fledged preparations for launching a new administration in the evening, party sources said, adding that talks were also planned with its two allies — the Social Democratic Party and Kokumin Shinto (People's New Party) — on forming a coalition government.

Meanwhile, Prime Minister Taro Aso said he will step down as LDP president to "take responsibility" for his party's defeat. An election to pick his successor as LDP chief will be held soon, he said.

An election victory for the Opposition that might change the course of Japan.

LDP Secretary General Hiroyuki Hosoda also said on NHK the party's top three executives have all told Aso they plan to resign.

"We'd like to straightly face the severe results. We will search our souls and start preparing for the next election," Hosoda said, adding that the LDP will overhaul its policies to gain more support.

The LDP also lost some big names in single-seat races, including former Foreign Ministers Nobutaka Machimura and Taro Nakayama, as well as Finance Minister Kaoru Yosano and former Finance chief Shoichi Nakagawa.

New Komeito suffered even worse, with party chief Akihiro Ota and heavyweights Kazuo Kitagawa and Tetsuzo Fuyushiba all defeated in their single-seat districts. They didn't "insure" themselves by putting their names on the party's list of proportional-representation candidates.

DPJ deputy chief Ichiro Ozawa declined comment before the poll results were complete but said "there is nothing (for voters) to worry" about concerning an impending change in government.

"We'd like to steadily implement what we have promised to the nation," Ozawa told NHK.

Pre-election media polls showed the DPJ leading the LDP thanks to strong populist tail winds propelled in part by frustration with years of stagnation and mismanagement under the LDP.

As many as 1,374 candidates, including a record 229 women, competed for seats in the 480-member chamber — 300 in single-seat districts and 180 in the 11 proportional representation blocks nationwide.

Due to strong voter interest, final turnout could reach 69.52 percent, exceeding the 67.51 percent in the previous general election in 2005.

A record 13.98 million people, or 13.4 percent of all eligible voters, cast early ballots.

Most of the nearly 51,000 polling stations opened at 7 a.m. and closed at 8 p.m.

The DPJ had just 115 seats before the election. The LDP, in contrast, was projected to capture as few as 100 or so, a shocking decline from its 300 seats before the race. New Komeito came in with 31 seats but had lost nearly half.

The LDP's fall would only be its second since it was founded in 1955. It was out of power for about 11 months between 1993 and 1994.

After campaigning officially began Aug. 18, Aso made clear his priority was to stimulate the economy, saying the economy is only halfway through its recovery.

He argued against giving a popular mandate to the DPJ on the grounds that the opposition party tends to waver on national security matters, and that his LDP is the only party responsible enough to govern.

The DPJ's Hatoyama promised to up support to households, saying a DPJ-led government will "cut waste created in bureaucrat-reliant politics and reorganize the budget in such a way as to spend money on what's really important."

The change in the Lower House will clear the legislative deadlock in the Diet, which has plagued the LDP-New Komeito ruling bloc for the past two years, when the less-powerful Upper House came under control of the opposition.

If the DPJ captures 321 seats or more, it would give the party more freedom to set the legislative agenda because the two-thirds majority would allow it to pass bills that are rejected by the Upper House.

But doing so could upset the DPJ's likely coalition partners and possibly destabilize their coalition government.

The DPJ and its likely coalition partners also differ over foreign policy and security issues, among other areas. The SDP, for example, opposes the dispatch of the Self-Defense Forces overseas, while the DPJ allows it conditionally.

Campaigning effectively began July 21, when Aso, 68, dissolved the Lower House. Since then, parties had pitched their policies to voters based on their campaign platforms.

In its platform, the DPJ pledges to cut wasteful spending, offer cash to households and keep the 5 percent consumption tax intact for the next four years, the duration of the term for new Lower House lawmakers.

But its big-budget policies, like the monthly child allowance to families, have been criticized as lacking specifics about sources of funding.