TOKYO -- The campaign to lead Japan's ruling Liberal Democratic Party officially kicked off on Friday. The triennial leadership election, which will effectively pick the successor to Prime Minister Yoshihide Suga, will be held on Sept. 29. What is the process? Here are five things to know.
How is the leadership election held?
The LDP was founded 65 years ago through the amalgamation of various conservative groups. In 1955, only members of the Diet and two representatives from each prefectural chapter were allowed to participate, according to Koji Nakakita, a professor at Hitotsubashi University. Since 1977, rank-and-file party members, 1.1 million of them in all today, have been allowed to vote.
Under the current system, party members and lawmakers have equal weight, or 383 ballots each, in the first round. If a candidate wins a majority of ballots at that stage, he or she wins. If no one wins outright, a runoff is held between the two leading candidates.
Rank-and-file party members are a diverse bunch. They include dedicated activists as well as members of industry groups, who are generally less committed to particular factions or politicians -- and tend to support the most likely winner.
Who are the candidates?
After Suga announced he would not seek reelection, there are four candidates: Taro Kono, the liberal and outspoken vaccine minister; Fumio Kishida, the establishment candidate; Sanae Takaichi, the hard-line conservative former party policy chief and a protege of Shinzo Abe, the former prime minister; and Seiko Noda, a former minister of internal affairs. If either Takaichi or Noda wins, Japan will have its first female prime minister.
Koichi Nakano, a professor of politics at Sophia University, said the fight is as much between the candidates as between the factions.
Party elders including Abe, Deputy Prime Minister Taro Aso and Akira Amari, a former economy, trade and economy minister, prefer the more amenable Kishida over the popular yet cheeky and independent-minded Kono, whose liberal agenda they mistrust. The election of Kono threatens to shift power to younger generations, and older members are therefore exerting factional influence to influence matters.
Kono also has support from other faction leaders, including Shigeru Ishiba, a former defense minister, and LDP Secretary General Toshihiro Nikai -- both Abe archrivals. Kono also has the backing of Suga and rising young stars like Shinjiro Koizumi and Tatsuo Fukuda.
What role do factions play?
Most of the LDP's 385 lawmakers belong to factions. The factions have less to do with leftist or rightist thinking, and more to do with the party's historical roots in various conservative groups. Others represent other interests, such as rural and urban groups.
Leadership elections used to be all about the factions, of which there are seven. The largest belongs to Shinzo Abe with 96 members. That is followed by the one led by Deputy Prime Minister Taro Aso with 53. Vigorous competition for power between the factions has been one of the reasons the LDP government has had such a high turnover in cabinet.
However, a growing number of lawmakers do not belong to any faction, including Suga. The ability of the factions to control their members has also withered. As a result, many factions have decided not to require their members to vote for particular candidates.
What is the likely scenario?
One scenario is that a winner emerges from the first round. This happens when one candidate wins a majority with solid support from rank-and-file members. Kono is pitching for this scenario by capitalizing on his strong name recognition and public popularity.
The other scenario is no clear winner and a runoff. Lawmakers account for 383 of the 430 ballots in the second round, and factions can play a more decisive role with their block votes.
In the 2012 leadership election, Shinzo Abe came second in the primary but won the runoff. He is apparently attempting a similar feat with his preferred conservative candidates -- Takaichi and Kishida -- to see off Kono.
What happens after?
The government is considering a special parliamentary session that would convene on Oct. 4 to formally elect the LDP's new leader as prime minister. Since the LDP-led coalition controls majorities in both houses of parliament, the party's new president is certain to become prime minister.
But the lower house is coming to the end of its four-year term on Oct. 21, and general elections will be held after Oct. 21.
If Kono is elected, there will be a strong public perception that the party has gone through a transformation. That could provide the LDP with a tailwind against the opposition in the autumn elections, Nakano said. If Kishida wins, it is likely to give the impression that "factions still prevail in the LDP," he said.
His view is echoed by Yasunori Sone, a professor emeritus at Keio University, who believes "the public image of the LDP could change completely," if Kono wins.