By Tetsushi Kajimoto and Linda Sieg
TOKYO (Reuters) - Japan's ruling Democratic Party formally kicked off a leadership race to pick the next prime minister as the country confronts a raft of economic ills, but with five candidates jostling for the job, no clear winner was in sight.
The race to select Japan's sixth leader in five years is shaping up as a battle between allies and critics of party powerbroker Ichiro Ozawa, a 69-year-old political mastermind who still wields clout despite facing trial on charges of misreporting political donations.
The successor to Prime Minister Naoto Kan, who on Friday resigned as Democratic Party of Japan (DPJ) leader after months of criticism for his response to the March tsunami and the nuclear crisis it triggered, faces a mountain of challenges.
The next leader must grapple with a resurgent yen that threatens exports, rebuild from the disaster, forge a new energy policy while ending the world's worst nuclear crisis since Chernobyl, and find funds to pay for the bulging social welfare costs of an aging society while reining in public debt already twice the size of the $5 trillion economy.
The impression that power struggles, not policies, are dominating the race risks further denting support for the Democrats, who swept to power in 2009 promising change. Nut their ratings have sagged due to policy flipflops, indecision and charges of a bungled response to the disasters.
"Moves in each candidate's camp to put priority on a numbers game are conspicuous," said an editorial in the Nikkei business daily. "If this sort of internal power struggle continues, trust in the Democratic Party cannot be restored."
Five lawmakers including fiscal conservative Finance Minister Yoshihiko Noda, trade minister Banri Kaieda and former foreign minister Seiji Maehara registered on Saturday to run in the August 29 party vote. The winner will become prime minister by virtue of the DPJ's majority in parliament's lower house.
POPULARITY VERSUS POWER
Maehara, a security hawk who says beating deflation is a top priority, is the most popular with ordinary voters. An Asahi newspaper poll published on Saturday showed that 40 percent of voters surveyed preferred the 49-year-old lawmaker.
"This is not just an internal party election. How to appeal to the people is important," the Asahi newspaper quoted Maehara as saying on Friday night.
But only DPJ lawmakers can vote in the party poll, so Maehara faces a tough battle against Kaieda, 62, who on Friday secured the backing of Ozawa -- who heads the DPJ's biggest group -- and his ally, former prime minister Yukio Hatoyama.
"This is a chance to show everyone our strength," Japanese media quoted Ozawa as saying on Friday.
Feuds over Ozawa, a former heavyweight in the long-dominant Liberal Democratic Party (LDP) who bolted the conservative party in 1993 and helped briefly oust it, have plagued the Democrats since his tiny party merged with the DPJ in 2003.
Some credit his electioneering skills with helping to sweep the DPJ to power in 2009. Others say his negative image and old-style methods are weighing down the party.
The outlook for Maehara, who stepped down as foreign minister in March after admitting he had unknowingly accepted donations from a Korean resident of Japan, is also clouded by Noda's candidacy, since their support bases overlap.
If no candidate wins a majority in an initial vote, the two top candidates will square off in a second round and media said both Maehara and Kaieda were already jockeying to woo backing from other candidates if that happens.
"The possibility is strengthening that no victor will emerge from the first round," said the Mainichi newspaper.
Despite Ozawa's backing, Kaieda -- who has been cautious about raising taxes too soon to curb public debt -- is not a shoo-in.
Critics have derided him for bursting into tears before TV cameras after being grilled in parliament over a rift with Kan over whether to restart nuclear power plants that have completed maintenance checks after the March 11 tsunami triggered a radiation crisis at the Fukushima atomic plant.
Nor does Ozawa, known as the "Destroyer" for his record of breaking up parties he once led, wield the clout he once held, and many lawmakers may be wary of selecting a leader likely to quickly be labeled an Ozawa puppet.
(Additional reporting by Osamu Tsukimori; Editing by Ed Lane)