science

Sanseitō

Sanseitō is a science 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 Sanseitō rather than just read about it. In short: Sanseitō (Japanese: 参政党, lit. 'Political Participation Party'; self-rendered as Party of Do It Yourself in English; DIY) is an ultraconservative, right-wing populist political party in Japan. It is on the far-right of the political spectrum.

Key takeaways

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

Reference excerpt

Sanseitō (Japanese: 参政党, lit. 'Political Participation Party'; self-rendered as Party of Do It Yourself in English; DIY) is an ultraconservative, right-wing populist political party in Japan. It is on the far-right of the political spectrum. The party was founded in 2020 by Sohei Kamiya, the current secretary general of the party, and won a seat in the 2022 House of Councillors election, also becoming an official political party by winning more than 2% of the vote in the election. Sanseitō gained international media attention during the 2022 House of Councillors election due to Kamiya's antisemitic rhetoric during public appearances and campaign rallies. In the 2024 general election, the party won 3 seats. In the 2025 House of Councillors election, the party won more than 14 seats and came in third in the national popular vote. According to the party's leader Kamiya, it is the Japanese equivalent of Trumpism in the United States. The party promotes COVID-19 misinformation. The party's president, Manabu Matsuda, has called COVID-19 vaccines a "murder weapon". The party is against same-sex marriage and LGBT rights. The party strongly opposes immigration, claiming that foreigners bring crime and receive better treatment than native citizens. It proposes the creation of a new constitution to replace the existing one and published a draft that contains minimal human rights protections.

History Sanseitō originated from a conservative YouTube channel called "Political Party DIY" created by streamer Kazuya Kyoumoto, politician Sohei Kamiya, and political analyst Yūya Watase in April 2019. The YouTube channel's objective is to show how to create a political party from scratch. In April 2020, the three founders of the YouTube channel officially started Sanseitō. At the end of 2020, Jōichiro Shinohara, a founding member of the party, advocated a conspiracy theory alleging that the 2020 United States presidential election was "rigged", causing infighting among him and two founding members, Kyoumoto and Watase, who were skeptical of the conspiracy theory. This led to three of the founding members leaving the party in 2021, while Kamiya remained as the leader of the party with Manabu Matsuda, another founding member of the five-person party. At this time, Kamiya was thinking about the direction of the party, and decided that he would be able to expand his support base by focusing more on conspiracy theories and network marketing. Since then, a large number of anti-vaccination and organic faith groups who claim that the COVID-19 vaccine is a conspiracy by pharmaceutical companies joined the party, creating a new support base. The party fielded five candidates for the national proportional representation block and 45 candidates in all constituencies for the 2022 Japanese House of Councillors election. Sohei Kamiya, a Sanseitō candidate in the national proportional representation block, won a seat. The party received more than 2% of the vote in the constituencies and proportional representation block, meeting the legal requirements for it to become a political party. In the 2025 Japanese House of Councillors election, Sanseitō secured 14 seats based on its "Japanese First" slogan and a policy of tax reduction. It has gained votes from voters who had no previous party affiliation.

Ideology and policies

Sanseitō is known for its ultraconservative ideology. It has also been referred to as extreme, "extremely conservative", and "hardline nationalist". Sohei Kamiya, founder and secretary general of Sanseitō, said that Sanseitō has a high affinity with the conservative faction of the U.S. Republican Party, the far-right German party Alternative for Germany (AfD), the far-right French party National Rally (RN), and the right-wing populist party Reform UK. Kamiya has said that he learned many of his "emotional button-pushing themes and norm-breaking language" from U.S. president Donald Trump and stated that he was Japan's equivalent of Trump. According to Kamiya, Japan faces threats from shady globalists ("cabal of global elites"), criminal foreigners and a corrupt political establishment that is suffocating young people with taxes. His has proposed a "Japanese First" nationalist agenda. Sanseito has drawn mainly young male voters. Opponents and domestic media reports have accused him of being xenophobic, saying he is directing public anger with high prices and stagnant wages at Japan's foreign residents.

Diplomacy and military

Relationship and view on Russia In July 2025, the party was accused of having ties with Russia after an upper house election candidate named Saya appeared in a Sputnik News interview, and for making payments to an advertising firm Vostok Joint Company. The party's general secretary Kamiya denied affiliations to Russia and claimed that the interview was authorized by a "low ranking staff" and that he was not informed beforehand. Kamiya said he has asked the responsible party staff to resign for authorizing the Sputnik interview. Sanseitō's relation with Russia has been questioned before as Kamiya said "Moscow should not be held entirely responsible for the war in Ukraine."

Security and defense The party advocates an increase in the national defense budget of up to 3% of GDP. The party is against the stationing of American troops and American military bases in Japan. The party calls for "constitutional reform and strengthening of the Self-Defence Forces". The party also says that "Sado Island and Tsushima should be made independent and a nuclear-armed nation should be created." Furthermore, Kamiya claimed that NISA could fund the development of a domestic social media platform to strengthen information sovereignty.

… excerpt ends here. Continue reading the full article.

Illustrations

Worked examples

Example 1 — a first encounter with Sanseitō

Start with the simplest possible case. Write down what Sanseitō claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, 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 Sanseitō 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 Sanseitō 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 Sanseitō

In research: Sanseitō appears in science 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 Sanseitō 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: Sanseitō is common in secondary-school and first-year university syllabi. It links to neighbouring topics 2020 establishments in Japan, Anti-Chinese sentiment in Japan, Anti-Korean sentiment in Japan, so understanding it makes those chapters shorter.
In everyday life: Look for Sanseitō 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.

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How to study Sanseitō in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Sanseitō 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 Sanseitō out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Sanseitō in simple terms?

Why does Sanseitō matter?

Because it connects several science 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 Sanseitō?

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 Sanseitō.