physics

Reiwa Shinsengumi

Reiwa Shinsengumi is a physics topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Reiwa Shinsengumi rather than just read about it. In short: Reiwa Shinsengumi (Japanese: れいわ新選組) is a progressive and left-wing populist political party in Japan founded by actor-turned-politician Taro Yamamoto in April 2019. The party was formed by left-wing members of the Liberal Party who opposed its merger with the Democratic Party for the People.

Key takeaways

Reiwa Shinsengumi belongs to physics; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Reiwa Shinsengumi to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Reiwa Shinsengumi from memory before moving on to harder problems.

Reference excerpt

Reiwa Shinsengumi (Japanese: れいわ新選組) is a progressive and left-wing populist political party in Japan founded by actor-turned-politician Taro Yamamoto in April 2019. The party was formed by left-wing members of the Liberal Party who opposed its merger with the Democratic Party for the People. The party won more than 4% of the vote after contesting the House of Councillors election in July 2019, gaining two seats only about three and a half months after the formation of the party. The party is named after the current era name Reiwa and the Shinsengumi of the Bakumatsu period. On 6 August 2026, the party announced it would be renamed Party of Life (いのちの党, Inochi no Tō).

History

Founding Taro Yamamoto, a member of the House of Councillors for Tokyo, founded the party on 1 April 2019. This was with the intent of standing multiple candidates, including himself, in the upcoming House of Councillors election later in the year. On 10 April, Yamamoto held a press conference and announced the party's platform.

2019 House of Councillors election The party stood multiple candidates in the 2019 House of Councillors election. The party won 2.2 million votes in the national PR block, exceeding the 2% threshold needed to be recognised as a political party, and securing two seats. Nearly one million votes were cast for Yamamoto personally; however, because the party had nominated Yasuhiko Funago and Eiko Kimura, both of whom have disabilities, ahead of him in the party list, Yamamoto did not win a seat. The National Diet Building was adapted to allow barrier-free access for wheelchair users. Notable party members include university professor Ayumi Yasutomi and former deputy representative of the North Korean abduction liaison Toru Hasuike.

2020 Tokyo gubernatorial election Yamamoto was one of the 22 candidates participating in the 2020 Tokyo gubernatorial election, coming in third place with 10.72% of the votes. The party promises included a direct cash handout programme due to the COVID-19 pandemic.

2021 Japanese general election Yamamoto joined with the leaders of the Constitutional Democratic Party, Japanese Communist Party, and Social Democratic Party in running a joint opposition coalition based on common policy goals. Yamamoto, who had been formerly running in Tokyo's 8th district, withdrew to run in the Tokyo PR block to avoid vote splitting against the CDP's Harumi Yoshida. The withdrawal came following pushback from local residents, who were hesitant to vote for Yamamoto, a "parachute candidate," over Yoshida, who had been active within the community for many years prior. The party further withdrew 7 candidates as part of the joint platform to avoid vote splitting between the opposition parties, accounting for 40% of Reiwa Shinsengumi's planned slate of candidates. There were 20 other candidates besides Yamamoto running under the Reiwa Shinsengumi banner, including Takashi Takai, who was expelled from the Constitutional Democratic Party of Japan after ignoring COVID-19 state of emergency laws. Takai was at that moment Reiwa Shinsengumi's only sitting legislator, formerly elected on the CDP list for the Chūgoku proportional representation block. Takai ran for Shiga Prefecture's 3rd District but was not elected. Reiwa ultimately won three seats in the House of Representatives, electing Yamamoto, Akiko Oishi, and Hayato Kinoshita.

2022 House of Councillors election Yamamoto announced his resignation from the House of Representatives seat to which he was elected in 2021 general election, and contested in Tokyo metropolitan constituency for the House of Councillors. Reiwa gained three seats in the election, bringing their total to five: Yamamoto winning a seat in Tokyo, along with two other candidates, Daisuke Tenbata and Hakase Suidobashi, who took up seats in the nationwide proportional representation block.

2024 Japanese general election Reiwa Shinsengumi won nine seats in the 2024 Japanese general election, tripling their seat count in the House of Representatives and winning 6.98% of the proportional representation vote.

2025 House of Councillors election Reiwa Shinsengumi won a total of six seats in the election, up one from 2019. On 21 January 2026, Yamamoto resigned from the House of Councillors after being diagnosed with multiple myeloma. He stated he would continue as party leader with a reduced workload.

2026 Japanese general election In the 2026 election, Reiwa Shinsengumi ran just 18 candidates. The party was reduced to one seat in the House of Representatives, down from nine, and achieved just under three percent of the vote, down four points from 2024. This is the party's worst result since its formation.

2026 leadership changes On 3 July 2026, the party announced that then-leader Taro Yamamoto had received a speeding ticket in October 2025 during a business trip. Yamamoto was fined ¥90,000 in Ōita Prefecture for driving 149 km/h (93 mph) in an 80 km/h (50 mph) zone, 69 km/h over the limit. His driver's license was suspended for 90 days. On 9 July 2026, Taro Yamamoto made announced his resignation as party leader of Reiwa Shinsengumi. His stated reason was health issues and the "inexcusable" speeding incident. Yamamoto also announced the resignation of other members of party leadership from their positions, including co-party leader Akiko Oishi and Secretary-General Joji Yamamoto. Oishi also announced her intention to leave the party. A leadership election was scheduled for 31 July 2026 with campaigning to begin on 17 July 2026. It was also determined that the party's name would be changed after the election, with Taro Yamamoto stating that he did not want to stand in the way of the party as “a relic of the past.” On 31 July 2026, Joji Yamamoto was elected as new party leader of Reiwa Shinsengumi.

… excerpt ends here. Continue reading the full article.

Illustrations

Worked examples

Example 1 — a first encounter with Reiwa Shinsengumi

Start with the simplest possible case. Write down what Reiwa Shinsengumi claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In physics, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Reiwa Shinsengumi before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Reiwa Shinsengumi ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Reiwa Shinsengumi

In research: Reiwa Shinsengumi appears in physics research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Reiwa Shinsengumi in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Reiwa Shinsengumi is common in secondary-school and first-year university syllabi. It links to neighbouring topics 2019 establishments in Japan, Animal welfare organizations based in Japan, Anti-nuclear organizations, so understanding it makes those chapters shorter.
In everyday life: Look for Reiwa Shinsengumi outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

Ask Teacher Smith questions about this articleOpens your AI tutor with a question about “Reiwa Shinsengumi” →

Affiliate

Preply — study more efficiently by working with a personal tutor. 50% off.

How to study Reiwa Shinsengumi in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Reiwa Shinsengumi means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Reiwa Shinsengumi out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Reiwa Shinsengumi in simple terms?

Why does Reiwa Shinsengumi matter?

Because it connects several physics ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Reiwa Shinsengumi?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Reiwa Shinsengumi.