This is considered one of the party's most unpredictable leadership elections in decades and could produce Japan's youngest prime minister or first female prime minister.

The race to succeed incumbent Prime Minister Fumio Kishida erupted in August when Mr. Kishida suddenly announced his decision to resign after a series of scandals sent the Liberal Democratic Party's approval ratings to a record low.

Polls show three front-runners among nine candidates: former Environment Minister Shinjiro Koizumi, 43; Economic Security Minister Sanae Takaichi, 63; and former Defense Minister Shigeru Ishiba, 67.

The LDP, which has ruled Japan for most of the postwar period and holds a majority in Japan's parliament, is due to hold a general election by October 2025. However, Shinjiro Koizumi has said that if he wins, he will hold a snap election that could come as early as next month.

The results of the vote, which involved 368 LDP lawmakers and grassroots members, are expected at around 2:20 p.m. today, Japan time.

If no candidate wins a majority of votes, a runoff vote will take place the same day between the two candidates with the most votes.

In the second round of voting, each lawmaker will again receive one vote, but the share of votes cast by grassroots members will be reduced to 47. The results will be known at 3:30 p.m. Japan time the same day.

Polls show Shinjiro Koizumi, son of former Prime Minister Junichiro Koizumi who served from 2001 to 2006, has the most support among lawmakers.

If he wins, he would become Japan's youngest prime minister, surpassing the country's first prime minister, Ito Hirobumi, who took office at the age of 44 in 1885, according to official records.

Meanwhile, Ms. Takaichi, a hard-line nationalist and supporter of former Prime Minister Shinzo Abe's "Abenomics" economic stimulus policy, still has a good chance of becoming the first female prime minister in Japan's notoriously male-dominated society.

Hoang Anh (according to NHK, Kyodo, Reuters)