"People want a party that can do something," says Tobias Harris, who runs the perspicacious observingjapan.com website. "They are not convinced that the DPJ is that party, but they are 100 percent convinced that the LDP is not that party."
How will the DPJ change things?
The biggest change, if DPJ leader Yukio Hatoyama can pull it off, will be in the way that Japan is governed. Mr. Hatoyama, scion of a prominent Japanese political family, has pledged to seize policy-making power from the senior civil servants who have wielded it for years, and hand it to elected politicians.
Other popular campaign promises included income support for struggling farmers, child allowances for parents, and the abolition of road tolls.
In foreign policy, the conservative-minded Hatoyama is not expected to shift Japan away from its close alliance with the United States, though he has said Tokyo will next year stop deploying refueling ships in support of coalition action in Afghanistan.
LDP's alliance system crumbled
The LDP would have had a hard time holding on to power at these elections regardless of how long it had been in office. Over the past year Japan has suffered its worst economic recession since the war, and unemployment is at a near record 5.7 percent.
The party was fatally weakened, however, by the collapse of the system that had sustained it for more than half a century.
The LDP's dominance rested on its alliances with a range of powerful interest groups such as the farm lobby, the construction industry, the Japan Medical Association, and a nationwide network of influential local postmasters.
Instead of appealing directly to individual voters, the party relied on these groups to get out the vote at elections. For decades they did so, in return for policies that favored them.