In August 2015,
Secretary General Kakizawa Mito endorsed a candidate jointly backed by the
Japanese Communist Party and the
Democratic Party of Japan in the
Yamagata mayoral election, exposing internal divisions within the
Restoration Party. On 28 August,
Tōru Hashimoto and his close ally and advisor, Osaka Governor
Ichirō Matsui, announced their departure from the party. The following day, Hashimoto declared his intent to establish a new political party. The announcement was supported by
House of Councillors member
Toranosuke Katayama and other Osaka-based lawmakers. Plans were made to call the new party the "Osaka Restoration Party" (), and preparations began for a formal split from the existing party structure. By October, the talks had broken down, prompting the national leadership of the Japan Innovation Party to expel members of the Diet and local assemblies who were expected to align with Hashimoto's new group. However, Osaka-based Diet members contested the expulsions, arguing they were legally invalid since, after 1 October, the party no longer had a valid executive structure. As a result, the expelled members filed a formal appeal against the decision. In protest, five House of Councillors members, affiliated with Katayama, voluntarily withdrew from the parliamentary faction on 16 October, forming a new "Restoration Party (House of Councillors)" faction. On 31 October 2015, Hashimoto and Matsui officially launched during a meeting in Osaka, following their departure from the Japan Innovation Party. The name was derived from the
Osaka Restoration Association, also founded by Hashimoto, but distinguished by the use of
hiragana () instead of
kanji (). The first significant election contested by the party was the
July 2016 House of Councillors election. The party saw strong results in the
Kansai region, winning two of the four seats in the
Osaka at-large district and one of three in the
Hyogo at-large district. In the national proportional representation block, the party placed fifth with 5,153,584 votes (9.2%), earning 4 out of 48 seats. The party's support was especially concentrated in Osaka, where it received 1,293,626 votes (34.9%), and it ranked second in Hyogo Prefecture with 470,526 votes (19.5%). The gains positioned the party as the third-largest opposition force in the
National Diet. Despite success in Kansai, Matsui declared the party's overall performance insufficient for a national political force. On 12 July, he announced plans to rename the party to broaden its appeal across Japan. An internal poll among Diet members and regional representatives shortlisted three names, with "Nippon Ishin no Kai" (Japan Restoration Party) emerging as the most supported. On 23 August 2016, during a special convention in Osaka City, the party formally adopted the new name: . Matsui continued as party leader, and the party unveiled a new logo similar to its previous design, replacing the word "Osaka" with "Japan."
2017 elections In January 2017, Nippon Ishin no Kai announced plans to field candidates for the Tokyo Metropolitan Assembly election scheduled for that summer. However, after Tokyo Governor
Yuriko Koike and her party, the
Tokyo Citizens First Association, declared they would not coordinate efforts, potential post-election cooperation was considered. On 22 June, Vice President Kimi Watanabe publicly expressed support for the Tokyo Citizens First Association and resigned. He was expelled from the party that same day. In the July 2 Tokyo Assembly election, despite support from party leader Matsui and Osaka Mayor Hirofumi Yoshimura, only one of Ishin’s four official candidates was elected, leaving its seat count unchanged. On 30 September, the
Kibō no Tō (Party of Hope) was established with Matsui named its representative. Tokyo Governor Yuriko Koike announced electoral cooperation between her party and Ishin for the 48th general election on 22 October. As part of the agreement, the Party of Hope did not run candidates in Osaka, while Ishin withdrew its Tokyo candidates. On 6 February,
Yutaka Hasegawa, a former
Fuji TV announcer, joined the party. On 28 January, he was named the branch chief for the Chiba 1st district and declared his candidacy for the next House of Representatives election. On 25 March, the party held its annual convention in Tokyo for the first time—traditionally held in Osaka—in anticipation of the upcoming election. During the event, six official candidates and the party's Tokyo manifesto were announced. During the general election on 22 October, the party secured only three seats, all from single-member districts in Osaka Prefecture, and faced challenges in its stronghold, ultimately obtaining 11 seats, including eight proportional representation seats, down from 14 in the previous election. The absence of Hashimoto, the former representative, the unsuccessful alliance with the Party of Hope, and the rise of the
Constitutional Democratic Party of Japan were cited as contributing factors to this outcome. On 26 January, Hodaka Maruyama, a member of the House of Representatives, tweeted: "Regardless of Representative Matsui's re-election, we need a summary of the Sakai mayoral election, the House of Representatives election, and the representative election." When Hashimoto called for a representative election, he remarked, "You won because Mr. Matsui is the governor. There's a way to express your desire to be elected. Bokeh!" He also stated, "It's detrimental to my mental health to interact with a Diet member who makes foolish comments. I despise such parliamentarians," and declared his resignation as a legal advisor to the Japan Restoration Association. Maruyama countered with accusations of "voter slander" and intolerance for being falsely represented. He initially submitted a resignation notice, but after Ishin retained the notice, Maruyama retracted it in January 2018. On 28 January, the Standing Committee convened, and an extraordinary party convention was scheduled for November according to the party statute. The convention's agenda included a policy decision on whether to conduct a representative election. On 25 November, following the general election results, an extraordinary party congress took place. The majority voted against holding a representative election, and Ichiro Matsui was confirmed to continue in his representation role.
2019 unified local elections and House of Councillors election On 23 January 2019, the House of Councillors representatives formed a unified parliamentary faction with the Party of Hope. Consequently, the total number of members reached 15, including
Kazuyuki Yamaguchi who had joined the Restoration Party that month, overtaking the
Japan Communist Party's 14 members to become the third-largest opposition party. During the 19th unified local elections in April, the Party of Hope was joined by New Party Daichi in Hokkaido and
Tax Reduction Japan in Aichi Prefecture. In Osaka Prefecture, the stronghold, Governor Matsui was elected as the mayor of Osaka, while Mayor Yoshimura won the gubernatorial election, both securing large margins over their opponents. The Osaka Prefectural Assembly and City Council saw an increase in seats, yet the party failed to win any prefectural elections outside its base, highlighting a limited national reach. After the passing of House of Representatives member Tomokatsu Kitagawa from the Liberal Democratic Party, Fujita Fumitake emerged victorious in the by-election for Osaka's 12th district on 21 April 2019. He triumphed over competitors including Shinpei Kitagawa, who is the nephew of the late Kitagawa, as well as Shinji Tarutoko and Takeshi Miyamoto. On 14 May, during a visa-free visit to the Four Northern Islands as part of an exchange project, Hodaka Maruyama disrupted a reporter's interview with islanders. He suggested "recapture by war" to resolve the Northern Territories issue. Maruyama refused to accept his resignation notice, and the board of directors subsequently expelled him. Following this, a bipartisan resolution condemning Maruyama's actions was submitted and unanimously passed in the House of Representatives on June 6.
2020: Tokyo gubernatorial election, second referendum rejection, and Matsui's retirement from politics In the Tokyo gubernatorial election on 5 July 2020,
Taisuke Ono, the former Deputy Governor of Kumamoto Prefecture, was a recommended candidate. Although a relative unknown, he secured 610,000 votes. However, he narrowly missed the threshold to retain his deposit, finishing in fourth place. Concurrently, in the Tokyo Metropolitan Assembly by-election, official candidates were fielded in the Kita Ward and Ota Ward constituencies, but both were defeated, with two LDP candidates winning the seats. On 1 November 2020, the second referendum on the
Osaka Metropolitan Plan, a key policy of Ishin no Kai, was rejected by a majority. That same day, Matsui announced his plan to retire from politics at the end of his mayoral term in April 2023. He also stated his resignation as president of the regional "Osaka Ishin no Kai", appointing Hirofumi Yoshimura as his successor. As for "Ishin no Kai" the national political party, he expressed a desire to consider his role separately from the Osaka Ishin no Kai and indicated he would continue in his position for the time being.
2021: Local elections, breakthrough at the 2021 general election, and new executive team Local elections In the Hokkaido 2nd district by-election on 25 April 2021, following Takamori Yoshikawa's resignation from the Liberal Democratic Party, former provincial councilor Izumi Yamazaki was defended. Muneo Suzuki, leader of the Hokkaido Restoration Party, supported the defense, stating "a conservative centrist receptacle is necessary" after the Liberal Democratic Party's defeat. However, Kenko Matsuki was elected, with Yamazaki finishing third and Yoshiko Tsuruha, an independent, as the runner-up. In the Takarazuka mayoral election in Hyogo Prefecture on 11 April 2021, Takashi Kado, a prefectural councilor from Takarazuka City, was officially nominated by his party. It was the first such nomination since the Takarazuka City and Itami City mayoral elections in 2013, which served as a prelude to the Hyogo gubernatorial election. Despite a vigorous campaign, Kado was narrowly defeated by Harue Yamazaki. For the Hyogo gubernatorial election, the Hyogo Restoration Association intended to nominate its own candidate since late 2020, but faced coordination challenges. In April 2021, a faction of the LDP Hyogo Prefectural Assembly opposed the executive department's policy and recommended Motohiko Saito, then head of the Osaka Prefectural Finance Division. In the Tokyo Metropolitan Assembly election, 13 official candidates were fielded. On 3 July, the day before the vote count, Matsui and Yoshimura delivered speeches in Tokyo to support their candidates. However, only one seat was secured, leading Matsui to comment on the difficulty of elections in Tokyo.
Breakthrough at the 2021 general election On 22 August, Secretary-General
Baba discussed the government's framework on a TV program, hinting at potential cooperation with the ruling party after the upcoming general election of the House of Representatives. He suggested that if allowed to pursue their desired policies, various forms of collaboration could be considered. On the 26th, Representative Matsui, reflecting on Baba's comments, stated there was no conflict with the Liberal Democratic Party and dismissed any coalition or cooperation with Jiko. Additionally, Matsui supported Prime Minister Yoshihide Suga's re-election in the LDP presidential election, citing the ease of collaboration between national and local governments, especially in combating the new coronavirus. In the recent general election, the party significantly increased its representation from 11 to 41 seats. In its stronghold of Osaka Prefecture, the party's candidates won in all but four of the 15 single-member districts, which were ceded to Komeito. Outside of the Osaka-Hyogo 6th district, the party also performed well in the Hanshin area. Nationally, the party improved its proportional representation vote tally by nearly 5 million from the previous election, securing 8.05 million votes and seats in 10 out of 11 national blocks, excluding Hokkaido. Party regulations required a decision on holding a representative election within 45 days after a major election. However, during an extraordinary party congress on 27 November, a vote among special party members, including National Assembly members and local councilors, resulted in 151 votes for and 319 against the election. Consequently, no representative election was held, and Matsui remained in the race. Furthermore, due to health issues, Toranosuke Katayama stepped down as co-representative, and Matsui suggested appointing Secretary-General Nobuyuki Baba as his successor. During the Standing Board of Directors meeting held on 30 November, Baba was officially appointed as the co-chair. Additionally,
Fumitake Fujita, a member of the House of Representatives, and
Shun Otokita, a member of the House of Councillors, were appointed as the chairman of the general affairs committee.
Hirofumi Yanagase, also a member of the House of Councillors, was named the secretary-general. The appointments for the Diet delegation were confirmed on the same day.
2023: Major unified election gains In April 2023, the party made significant gains in
local elections, more than doubling its seat totals in various local assemblies to 124. Notably, the party also captured the governorship of
Nara prefecture through its candidate
Makoto Yamashita. Two weeks later the party's candidate
Yumi Hayashi took
Wakayama 1st district in a
by-election.
2025: Governing coalition with the LDP After Prime Minister
Shigeru Ishiba was replaced as president of the
Liberal Democratic Party (LDP) by
Sanae Takaichi on 4 October 2025,
Komeito (the LDP's longtime
coalition partner) announced it would leave the government, as it refused to support Takaichi as Prime Minister. On 15 October, Takaichi asked Ishin leader
Hirofumi Yoshimura to enter into a coalition with the LDP. Around the same time,
Jun Azumi, the Secretary-General of the
Constitutional Democratic Party (CDP), was calling for opposition unity in the upcoming vote for Prime Minister. His proposal was for the opposition bloc to collectively back
Yuichiro Tamaki, the leader of the
Democratic Party for the People (DPP), rather than the CDP's own leader,
Yoshihiko Noda. Had the JIP aligned with this move, there was a significant possibility that Tamaki, rather than Takaichi, would have been elected Prime Minister. However, the JIP ultimately rejected the opposition’s overtures and chose to align with the LDP. On 19 October, it was announced that the LDP and the JIP agreed to form a
coalition, but without any Ishin members serving in the
Takaichi Cabinet. The following day, Takaichi was confirmed as the country's first female prime minister. == Ideology, platform, and policy ==