As campaigning for the Democratic Party's presidential election kicked off Friday, the single most daunting challenge shared by all three candidates was how to revive the nation's biggest opposition party.

Competing for the Sept. 15 election are Renho, 48, Seiji Maehara, 54, and Yuichiro Tamaki, 47.

"This election has to be the start of a new generation," said the front-runner Renho, who goes only by one name. She and Tamaki are among the DP's third generation of politicians, while Maehara and current party chief Katsuya Okada are from the second generation.