TOKYO (Kyodo) -- Japan is heading to a pivotal 465-seat House of Representatives election on Oct. 27, with the ruling Liberal Democratic Party battling to retain power amid a high-profile slush fund scandal that has severely eroded public trust in politics.

The upcoming general election, the first in three years, will take place just a month after Prime Minister Shigeru Ishiba won the LDP's presidential race on Sept. 27, marking the fastest that a new leader in postwar Japanese history is pursuing a public mandate.

Ishiba dissolved the lower house on Wednesday, one year before its term expires in October 2025. Official campaigning for the election, in which voters will decide whether to allow the LDP to continue managing the government, began on Tuesday.

Of the 26 lower house elections held since the present Constitution was enacted in May 1947 after World War II, only one, in 1976, was conducted without the chamber being dissolved as the four-year term of its members reached full expiration naturally.

The lower chamber, which is more powerful than the House of Councillors, has generally been dissolved mid-term with the prime minister calling an election. On four occasions, the chamber faced dissolution following the passage of a no-confidence motion against the Cabinet.

The upcoming lower house election will mark the sixth time one has been held in October, the highest number for any month. In Japan, upper house elections, in which half of the chamber's six-year-term seats are contested, are typically conducted in the summer every three years.

(By Peter Masheter)

Kuniaki Nemoto, a professor of political science at Musashi University, said the prime minister may have attempted to dissolve the lower house after summer and before an ordinary parliamentary session convenes each January.

The ruling coalition of the LDP and its junior partner, the Komeito party, must secure a majority of 233 seats in the lower house to maintain power. To achieve an "absolute majority" and control all 17 of the chamber's standing committees, they would need 261 seats.

In the previous lower house election on Oct. 31, 2021, held just weeks after Fumio Kishida became prime minister, the LDP alone obtained 259 seats. This figure was down 17 from the 2017 election but surpassed the 261-seat absolute majority threshold with Komeito's 32 seats.

Under Japan's election law, 289 are elected from single-seat districts and 176 through proportional representation in 11 regional blocks. Voters cast two ballots -- one for a candidate in their constituency and the other for a political party.

Candidates running in a single-seat district can also be placed on their party's list for proportional representation. If their party wins seats in the regional block, these seats are filled by candidates in the order in which they appear on the list.

So that means, even if such candidates lose in their single-seat constituency, they could still earn a seat through the proportional representation vote if their party receives enough support. This is sometimes called the "consolation round," a system that has faced criticism from some voters.

More than 1,300 people are running in 2024, with 314 women filing their candidacies, the biggest number in a lower house election under the current Constitution. The past record was 229 in 2009, when the opposition camp ousted the LDP from power.

In 2021, only 45 female candidates were elected to the lower house, accounting for 9.7 percent of the total seats. The election was the first since a law designed to promote gender equality in the political arena was introduced in 2018.

This year's lower house election is also being held for the first time since the country's largest-ever change to the distribution and boundaries of single-seat districts to rectify a vote-value disparity ruled to be in a "state of unconstitutionality."

The revision includes adding 10 single-seat constituencies to five prefectures while cutting one each from 10 prefectures, with an eye to narrowing the vote disparity below the 2-fold level between densely and sparsely populated districts.

In all, the changes would affect 140 single-seat constituencies in 25 prefectures, with the capital of Tokyo gaining five extra seats. The LDP, which has been in power for most of the period since 1955, is typically more popular in rural parts of Japan.

The LDP "has a really hard time winning seats in urban areas" as more people have moved to Tokyo over the past 20 to 30 years," Nemoto said, adding the situation "might make it difficult" for the ruling party to keep its majority in the lower house.