The Basics of Japanese Politics: What Role Does the Diet Play? How Many Political Parties Are There?

The 2020 Tokyo gubernatorial election set for next month is fast approaching.

Hopefully, more and more people are looking at candidates and their policies, trying to educate themselves before voting. 

At the same time, there will be people who want to learn more but don’t have the time to look for the information.

The goal of this post is to help educate those readers on the basics of Japanese politics—in particular, political parties and the Diet (assembly). In addition, this post will explain the political leanings of major media outlets.

A separate post will focus on the Tokyo assembly and the political parties represented there. 

The hope is that by understanding the basics, more people realize how important and interesting politics can be. 

What are Political Parties?

To be recognized as a political party, an organization must satisfy 2 conditions outlined in the Public Offices Election Act:

  • At least 5 politicians from the party are members of the Diet
  • In the latest national election, the party must have obtained at least 2% of the entire electoral vote

If these conditions are not met, the political party is recognized as a political organization instead.

Being a political party has its benefits. Besides media exposure, parties are able to receive public funding

This was a result of a series of reforms in 1994 aimed at reducing the number of corruption scandals (see the Recruit Scandal). The idea was that public funding from the government would prevent corruption. 

This subsidy provides parties 250 yen per Japanese citizen in relation to the number of Diet members they have in the party and the proportion of votes won in a national election.

These are public expenses that can be used for political activities such as setting up an office in the district, hiring staffers, and paying other administrative fees. 

Besides this subsidy, politicians can make money by receiving donations from corporations or political organizations, as well as through parties hosted by their koenkai (support organization run by citizens in their district).

Like America, there are limits to the amount of money that can be donated.

How Many Political Parties Exist? What Do They Stand For?

Currently, there are 9 active political parties in Japan. The Liberal Democratic Party (LDP) and Komeito Party run the coalition government and are known as renritsu yotou (連立与党). Opposition parties are known as yatou (野党).  

This is how the parties would line up in terms of ideology:

Liberal Democratic Party (LDP)

  • Conservative party established in 1955; they have run the government for more than 60 years in the post-WWII era (stability)
  • Focus on amending the Constitution and value the Japan-US alliance 
  • Strive to be the “people’s party
    • Economic growth
    • Enhancing social security 
    • Education reform 
  • PM Shinzo Abe has become the longest serving LDP leader and prime minister of the country


  • Party founded by members of the religious movement Souka Gakkai
  • Formed a coalition with the LDP in 1999
  • Policies
    • Enhancing social security as well as reducing the financial burden of education 
    • Pursuing happiness for people and the human race through peaceful diplomacy and disaster relief/preparedness

Constitutional Democratic Party (CDP)

  • Largest opposition party founded after the 2017 lower-house election which split the Minshinto Party (民進党) into 2 (originally part of the Democratic Party of Japan)
  • Established by leader Yukio Edano and others who opposed Minshinto’s merger with Tokyo governor Yuriko Koike’s Party of Hope (now the Tokyoites First Party) 
  • Focus on upholding the Constitution and oppose amendments during Abe’s tenure 
  • Believe the Self-Defense Force should not be written into the Constitution

National Democratic Party (NDP)

  • The other party that emerged from the Minshinto split in 2017; leader is Yuichiro Tamaki
  • Another reported merger with the CDP was on the table, but it failed again 
  • Sees itself as a moderate/center lane reformist party 
    • Wants to build an inclusive society for a diverse array of people 
    • Policies: Reducing work hours, increasing child allowance and rent subsidies

Japan Innovation Party

  • Founded as the Osaka Innovation Party in 2010 by then-Osaka governor Toru Hashimoto to achieve the Osaka metropolis plan (Osaka to-kousou)
  • Now known as the Japan Innovation Party and led by Osaka mayor Ichiro Matsui 
  • Policies
    • Supports Constitutional amendments (in line with the LDP/Komeito coalition)
    • Free education up through university 
    • Osaka metropolis plan (to make it like Tokyo)

Japan Communist Party (JCP)

  • Established in 1922 (deemed an illegal organization before the war)
  • Policies
    • Oppose Constitutional amendments and the Japan-US security alliance
    • Oppose national security legislation and Okinawa US-base relocation pushed by the Abe cabinet
    • Propose abolishing nuclear energy and using natural/clean energy

Social Democratic Party (SDP)

  • Founded in 1996; used to be one of the major parties in the 2-party system (the other was the LDP) known as the “1955 system
  • Policies
    • Shrinking the Self-Defense Force
    • Oppose raising the consumption tax
    • Oppose rewriting Article 9 and amending the Constitution 

The Party to Protect the People From NHK (N-Koku)

  • Created in 2013 for the sole purpose of ensuring NHK (Japan Broadcasting Corporation) broadcasts were scrambled, so only those who paid would be able to watch its programs

Reiwa Shinsengumi

  • Founded in 2019 by former actor Taro Yamamoto; name comes from the Shinsengumi special police force established during the later period of the Tokugawa shogunate
  • Met the requirements to be recognized as a party in the 2019 upper-house election
  • Policies
    • Abolish the consumption tax
    • Abolish nuclear power plants immediately
    • Repeal legislation passed during the Abe cabinet’s time such as the Legislation for Peace and Security of Japan
    • Raise the national minimum wage to 1500 yen 

Media Bias

Like other countries, Japanese media outlets also lean in certain directions on the political spectrum. However, the meaning of left/right can be quite difficult to understand at first glance.

In Japan, the distinction between the right and the left is whether tradition is valued, and whether you support Constitutional amendments (very broadly).

If you value tradition (like opposing husbands/wives from taking different surnames) and want to amend the Constitution, then you are likely to be a conservative. 

Due to the Broadcasting Act, TV channels are required to remain politically “fair” or neutral. In fact, you may be surprised to see how “un-political” news in Japan is compared to CNN or Fox News in America. 

Newspapers are different. In a vague sense, the major newspaper companies align like this:

  • Conservative/right: Yomiuri & Sankei Shimbun (newspaper)
  • Neutral: Nikkei Shimbun
  • Liberal/left: Asahi, Mainichi, and Tokyo Shimbun

This is something to keep in mind when you read news articles or commentaries (Japanese or English).

The Role of the Diet

The Constitution divides the powers of the state into three: the legislative branch (the Diet), the judicial branch (the courts), and the executive branch (the Cabinet). Similar to the US, they act as checks and balances on each other. 

Under the Constitution, the Diet is the “highest organ of state power, and shall be the law-making organ of the state.” As the branch most directly chosen by the people, the Diet is the most important branch of the state. Only the Diet can enact laws. 

The Diet is bicameral and consists of the lower-house (House of Representatives; shuugi-in in Japanese) and the upper-house (House of Councillors; sangi-in in Japanese)

Like the 3 branches of government, the two houses keep each other in check. The aim is to reflect a broad array of interests and ensure careful deliberation of the issues. 

Below are the responsibilities of the Diet as a whole:

  • Enacting the law 

Legislation can be introduced by the Cabinet or members of the Diet and are then discussed and eventually put to a vote

  • Voting on the budget and other legislation regarding the country’s financial affairs

The Cabinet sends a budget proposal to the Diet, where both Houses will discuss and eventually vote on the budget  

In the following fiscal year, the Diet assesses whether the Cabinet used the budget properly

  • Voting to accept/reject treaties with other countries

The Diet has the power to approve/reject treaties signed by the Cabinet

  • Nominating a prime minister

1) A member of the Diet wins their party’s leadership election (most of the time the leader of a party is a member of the lower-house)

2) Once named the leader of the majority party, if a simple majority (51%) in both Houses approve, the leader is nominated to be prime minister

3) The leader is officially recognized as the prime minister after the Emperor appoints/approves in a ceremony

  • Beginning the process to amend the Constitution

A supermajority (more than ⅔) in both Houses must agree to amend the Constitution

What Happens if the Diet Disagrees on a Decision?

The following chart shows what happens if the lower-house passes a bill, only for the upper-house to reject it. 

Article 59 of the Constitution says that a supermajority of the members present in the session can pass the bill in a revote. This gives the lower-house the power to override the upper-house in a second vote. This is a power only granted to the lower-house.

However, if the upper-house does not vote on a bill passed by the lower-house within 60 days, the bill is automatically rejected. This means the upper-house can stall on purpose and kill legislation.

This is one way the upper-house (and an opposition party that only holds a majority in the upper-house) can retaliate.

Since the Diet is only in session 150 days, stalling for 60 days may end up killing the bill entirely. This prevents the lower-house from ever getting to a revote during the 150-day session. 

In addition to this, if both Houses don’t agree on a bill, a joint committee can be established to sort out the differences.

Besides legislation (approving the budget, treaties, and nominating a prime minister), all matters must go through the joint committee. The lower-house can request a joint committee for other legislative matters if necessary

The committee is made up of 10 members from each House. If a supermajority of the 20 committee members approve the compromised bill, it is sent back to both Houses for a revote.

If the committee fails to reach a consensus, the lower-house’s decision is prioritized and becomes the final decision. For all legislative matters besides budgetary issues, treaty matters, and naming a prime minister, a ⅔ supermajority of the lower-house must approve the revised bill. 

As we can tell by now, the lower-house is given more power in the Diet than the upper-house. 

The Differences Between the Two Houses

Why is the lower-house given more powers? The answer lies in the difference between the two Houses.

House of RepresentativesHouse of Councillors
465 members245 members
Election every 4 years (unless the PM dissolves the house and calls an early election)Election every 6 years (½ of the seats up for election every 3 years)
Need to be 18 to vote | Need to be 25 to run for officeNeed to be 18 to vote | Need to be 30 to run for office
289 single-member districts
176 seats allocated by proportional representation (parties receive seats according to the number of votes they get as a party)
147 members from prefectural districts (only Tottori/Shimane & Tokushima/Kochi share 1 district)
98 members chosen by proportional representation
Can be dissolved by the prime ministerCan’t be dissolved

To summarize, the lower-house has more members, shorter terms, and can be dissolved. This makes this house much more representative of the people’s interests. As a result, more authority is allocated to them.

The lower-house also begins all budget deliberations/votes (Article 60). They can also request Diet sessions to be extended, ask for extraordinary or special Diet sessions, and call for a joint committee to be established (for legislative matters besides the 3). 

The lower-house can also introduce a vote of no-confidence to the floor. This is sent to the floor when members deem the PM or the Cabinet unfit to hold their position.

If ⅔ of the lower-house members are present and ¾ of them agree, the motion is passed. The prime minister then has 10 days to decide whether to dissolve the lower-house in hopes of maintaining power or have the entire Cabinet resign

On the other hand, the upper-house is often called the “House of Common Sense.” They have less members, longer terms, and must be 30 years old to run for office. The hope is that a variety of experienced people deliberate and act as a check on the lower-house. 

While this makes the upper-house seem like the Senate in America, the recent victories for athletes and show-biz people (based on name recognition) tarnishes that reputation. Still, the upper-house remains essential to maintain balance in the Diet. 

The upper-house also plays a crucial role when the lower-house is dissolved. If there are emergency decisions that must be made, the upper-house can hold an emergency meeting to continue the Diet’s work.

This ensures the Diet continues to function at all times, and is yet another reason why the upper-house is necessary in the Japanese political system.

The Current Diet

The Diet just ended its 201st ordinary session. One session is 150 days long, and because no extraordinary session was called, the session ended on June 17. 

The Diet can always call an extraordinary or special session. Extraordinary sessions are requested when members feel further deliberation on an issue is necessary. It requires at least ¼ of the members in either House to make the Cabinet call an extraordinary session. 

In the 201st session, the opposition parties had requested an extension of the ordinary session to no avail. Extensions are allowed once every ordinary session and twice every extraordinary or special session.

This time, the Cabinet decided it was unnecessary to extend the session.

A special session is called after the lower-house is dissolved and an election takes place. There, the members of the Diet nominate the prime minister.

At the moment, this is how the Diet’s seats are distributed:

House of Representatives
House of Councillors

In the lower-house, the LDP/Komeito faction hold a sizable majority of the seats.

However, the coalition doesn’t get close to the ⅔ supermajority in the upper-house necessary to vote on a Constitutional amendment. 

Understanding the distribution of elected seats in the Diet helps understand politics better. The number of seats can determine whether or not a party pursues a certain agenda.

Understanding Japanese politics will make the news seem more relevant. Just learning the vocabulary helps you feel closer to the news that may otherwise seem irrelevant. 

Knowing the political parties and the role of the Diet will also help you when choosing who to vote for.

In summary, Japan has 9 active political parties, of which two—the Liberal Democratic Party and Komeito—run the government. Despite having different views on policy, the opposition parties are slowly coming together under the anti-Abe banner. 

The Diet consists of the powerful House of Representatives, and the balancing power, the House of Councillors. Both play a unique role to ensure the Diet operates as the legislative branch of government. 

I strongly believe that understanding the basics will help you vote. While it may not help you discover a political party you align with, it definitely makes your vote much more meaningful. 

Sources (Japanese):

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