Campaigning began Tuesday for the Oct. 22 House of Representatives election, pitting the ruling coalition led by Prime Minister Shinzo Abe against a recently reorganized opposition including Tokyo Gov. Yuriko Koike’s Kibo no To (Party of Hope).

Reforms have shrunk the Lower House by 10 seats to a postwar low of 465. Abe has said he will resign if his Liberal Democratic Party and its smaller coalition partner, Komeito, do not win an overall majority with a combined 233 seats.

Abe kicked off his campaign in Fukushima, as he did in the last two Lower House elections, seeking to highlight his administration’s work on recovery from the March 2011 earthquake, tsunami and nuclear disasters.

“Recovery is moving forward without a doubt,” Abe told the crowd.

In Hokkaido, Komeito leader Natsuo Yamaguchi said his party “will change the way we use tax revenue and reduce the burden of (paying for) education.”

When he dissolved the Lower House on Sept. 28, Abe said he would seek a fresh mandate for his administration’s handling of heightened tensions over North Korea, as well as its decision to spend more of the revenue envisioned from a planned consumption tax hike on social welfare and less on paying down government debt.

He called the snap election — the Lower House members’ current term ends in December 2018 — apparently aiming to give the opposition as little time as possible to mount a united challenge to the ruling coalition he has led for nearly five years, though it has triggered a realignment of opposition forces.

Since then, Kibo no To has vowed to take down the Abe administration, seeking to distinguish its own “reform-minded conservative” platform from that of the coalition. The party has promised to freeze the tax hike scheduled for October 2019, impose taxes on retained corporate earnings and eliminate nuclear power plants by 2030, stressing that it can more drastically implement reforms since it is not tied to vested interests.

Koike, who was a lawmaker with the LDP before she ran for governor last year, has said she will not quit her current job to return to the Lower House.

Koike on Tuesday gave her first address of the official campaign in front of Tokyo’s Ikebukuro Station, part of a district she used to represent as a Lower House lawmaker.

“It’s the job of politicians to give people hope and dreams. We will win back people’s trust in politics,” Koike said.

Kibo no To announced Tuesday it will field a total of 235 candidates.

With the party still having not specified its pick for preferred prime minister in lieu of Koike, voters choosing the party may have to accept a degree of uncertainty and bet that she will be able to smoothly lead the party from outside the Diet.

Meanwhile, the main opposition Democratic Party has split, with more than 100 of its conservative-leaning members being allowed to join Kibo no To and its more liberal members forming the new Constitutional Democratic Party of Japan, led by former Chief Cabinet Secretary Yukio Edano.

Edano made his party’s first campaign remarks in Sendai, which was hit hard by the 2011 disaster.

“We want to bring proper lifestyles back to the people, and for that we need to bring propriety back to politics,” Edano said.

Both the LDP and Kibo no To are in favor of amending the war-renouncing Constitution for the first time since it came into force in 1947, but the LDP has put a greater emphasis on adding an explicit mention of the Self-Defense Forces after having pushed security legislation through the Diet last year to expand the troops’ roles.

The CDP argues that the security legislation introduced by the Abe administration is unconstitutional, and for that reason opposes adding a mention of the SDF’s status in the Constitution. It has said it will not field candidates in districts where those hailing from the Democratic Party are running.

Democratic Party leader Seiji Maehara and other senior members are set to run as independents.

Other parties include the Japanese Communist Party, the Social Democratic Party, Nippon Ishin no Kai and the conservative Kokoro wo Taisetsu ni Suru To (Party for Japanese Kokoro).

A total of 1,180 people registered their candidacies.

According to a Kyodo News tally, 332 were from the LDP, 235 from Kibo no To, 53 from Komeito, 243 from the JCP, 78 from the CDP and 52 from Nippon Ishin.

This election is the first for the Lower House since the voting age was lowered to 18 from 20 in June 2015.

Laws passed in the House of Representatives are referred to the smaller House of Councilors, or Upper House, which cannot be dissolved at will by the prime minister. Half of its 242 seats go up for re-election every three years.

The following is an explanation of how members of the House of Representatives — also known as the Lower House — are elected:

Under the revised electoral law that took effect in July, the number of Lower House seats has been reduced to 465 from 475. The revised Public Offices Election Law, aimed at reducing voting weight disparities between densely and sparsely populated districts, redrew boundaries in 97 districts in 19 prefectures.

Out of the 465 seats, 289 are elected from single-seat districts and the remaining 176 through proportional representation in 11 regional blocks.

Each voter casts two ballots — one to choose a candidate in a single-seat district and the other to select a party for proportional representation.

A candidate who runs in a single-seat district can also appear in the candidate list for proportional representation.

Even if such a candidate loses in their district, he or she could still secure a seat under the proportional representation method — if the candidate’s party gains sufficient votes — in a system dubbed a consolation round.

Political parties and groups which have five or more Diet members — or gained 2 percent or more of the total valid votes in the previous national election — can submit lists of candidates for proportional representation and will be given seats in accordance with their share of regional block votes. They then grant the block seats to candidates based on the order of their lists.