TOKYO, Sept 27 (Reuters) - A group of junior lawmakers has emerged as a force to be reckoned with in Japan"s ruling party leadership contest, facing off with party barons in the wide-open race for votes on Wednesday, which will also determine the premiership. Many of the 90-strong members of the grouping, who rode into power on the coat-tails of former prime minister Shinzo Abe, fear losses in a general election within months of the leadership race, and chafe at party customs, including the weakening but still present grip of old guard factions. "There"s no transparency in how they operate, no explanation," lawmaker Keitaro Ohno, 53, one of the founders of the Group for Renewing Party Spirit, told Reuters, referring to the established factions. "Even if we can operate pretty freely, when it comes time for leadership races and big party events, we"re told from the top "hey you guys, look right". If you ask "why right?", they"ll say "Just listen to me. If I say it"s right, it"s right." This isn"t good." Though similar groups have formed throughout the history of the ruling Liberal Democratic Party (LDP), this one appears to be having an impact. Due to its pressure, party barons have ruled that members of the formal factions can vote as they wish on Wednesday. All four candidates for party leader - who will almost certainly become prime minister as leader of the biggest party in parliament - also joined a debate with the group"s top members, apparently looking to win backing. Though analysts believe many members of the group will choose vaccine minister Taro Kono, it isn"t endorsing any candidate. Ohno supports former foreign minister Fumio Kishida - who has talked about party reform, including term limits. The old party factions have lost influence since reforms in the 1990s when they were banned from funding candidates, leaving that solely to party headquarters. Now they mostly jostle for cabinet and party posts. "ENERGETIC" Though Ohno said party elders can have useful experience, and factions can be helpful, voters tell him and others they"re increasingly distrustful of old-style politics, characterised by backroom deals, like the way Prime Minister Yoshihide Suga was chosen last year. Members of the group say they have to take the initiative to win over voters. "I hear talk that our ability to communicate is weak, that we have to do what the elders want," said Arata Takebe, a 51-year-old Hokkaido lawmaker, in a video on his website. "If the younger members aren"t energetic the LDP isn"t appealing. That"s why we have this group." Rebels they"re not. Many, including Ohno and Takebe, are second- or third-generation politicians. Group leader Tatsuo Fukuda, 54, is the son and grandson of prime ministers. Many have corporate experience like Ohno, an ex-researcher at electronics firm Fujitsu who held a fellowship at a U.S. university. They also matured after Japan"s economic bubble burst, which Ohno said means they don"t take things for granted. "Younger Diet members feel like they have nothing to do, they"re cut out, they haven"t earned their service time so they have to be quiet and just do what they"re told, and who likes that?" said Tobias Harris, senior fellow at the Center for American Progress. The pressure of an imminent general election - one has to be held by Nov. 28 - has given the younger politicians leverage for change, Harris said. "The circumstances of this election gave them an opening which they"ve used to weaken factional control over the outcome." Ohno, who has not identified himself with any of the party"s old factions, hopes his group can fulfil what he says are widespread voter hopes for a more contemporary political system. "That means breaking away from the Showa-era style of political management," he said, referring to the period from 1926-1989, corresponding with the reign of Emperor Hirohito. "And, modernisation."