Is the Suddenly Proposed "Reduction of Parliamentary Seats" Really Necessary? - The Gateway to Institutional Reform or a Diversion of Issues? [Part 2] Looking at Japan's Number of Legislators Through Data - Pros and Cons of Reduction

Review of the previous session

In Part 1, we reviewed how the initial focus of the coalition talks between the Liberal Democratic Party and Nippon Ishin no Kai, which was "regulation of corporate and organizational donations," shifted unexpectedly to "reduction of parliamentary seats."

We also looked in detail at the historical transition of Japan's electoral system and the structural issue of the "disparity in the value of a single vote." The number of parliamentary seats has been reduced in stages from 512 in 1990 to the current 465.

However, correcting the "disparity in the value of a single vote" is a matter of seat allocation and redistricting, which is a separate discussion from a simple "reduction of seats." While the judiciary has repeatedly called for corrections, the difficult challenge of how to protect local voices has also emerged.

Perspective of Part 2

This time, we will examine the reality of the number of legislators in Japan based on more concrete data. Is the assertion that "the number of legislators has not decreased despite the declining population" correct?

Compared to other countries, is the number of legislators in Japan really too high? And what are the pros and cons of reducing parliamentary seats? We will examine this from multiple angles, including economic effects, reflection of public opinion, and the impact on parliamentary functions.

5. Population decline and the number of legislators - Reality seen through data

One of the grounds for the opinion calling for a "reduction of parliamentary seats" is the point that "the number of legislators has not decreased despite the population decline." So, what is the relationship between Japan's population trends and the number of national legislators?

Relationship between population and the number of legislators

According to census data, Japan's total population had been increasing for many years, but it turned to a decline after peaking at 128.08 million in 2008. Estimates by the National Institute of Population and Social Security Research suggest that it will continue to decline in the future.

On the other hand, as mentioned above, the number of seats in the House of Representatives has been reduced in stages from 512 in 1990 to the current 465 seats. In other words, the number of parliamentary seats was already on a downward trend even before the population peak.

Comparison with other countries: In a comparison with developed countries, the total number of seats per 100,000 people is 0.57, which is 33rd out of 34 OECD member countries, a fact that shows the number of seats is extremely small relative to the population.

While parliamentary systems differ greatly from country to country and simple comparisons are difficult, I will provide rough estimates to see the trends. The number of national legislators per 1 million people in Japan is 5.8, which ranks 5th highest among the top 20 countries by population.

On the other hand, if we change the comparison target to the G7, Japan's ranking becomes 6th (2nd lowest), following the UK (21.1 people), France (14.3 people), Canada (11.1 people), Italy (10.3 people), and Germany (9.7 people).

Although international comparisons have limitations due to differences in each country's system, such data serves as one of the materials to verify the argument that "the number of legislators in Japan is excessive."

6. Pros of reducing parliamentary seats - Economic effects and reflection of public opinion

So, what are the benefits of reducing parliamentary seats? Let's examine them from various perspectives.

Economic effects

The most obvious benefit is the reduction of legislative expenses. The annual salary of a national legislator is said to be about 21 million yen. If 50 seats in the House of Representatives were reduced, it would be a simple calculation of a reduction of about 1.05 billion yen per year.

In addition to this, expenses such as the document, correspondence, transportation, and accommodation allowance (12 million yen per year) provided to each member, as well as secretary salaries, will also be reduced.

Rapid decision-making

With fewer Diet members, there is a possibility that the speed of decision-making will increase. There is an argument that, especially in committee deliberations, limiting the number of participants in discussions allows for more efficient debate.

Symbolic significance as 'reform that cuts into one's own flesh'

When asking the public to bear a burden, it demonstrates a stance where politicians themselves share the pain. This is important as a psychological effect and may lead to the restoration of trust in politics.

However, these are merely 'possibilities' and there is no guarantee they will be automatically realized.

7. Disadvantages of reducing the number of Diet members - Loss of diversity and representation

On the other hand, there are also serious disadvantages to reducing the number of Diet members.

Loss of diversity in public opinion

If the number of Diet members decreases, it becomes that much more difficult to reflect diverse public opinion in the Diet. In particular, if the number of seats is reduced under the proportional representation system, it becomes even harder for minority parties to win seats, creating a risk that diverse opinions will be excluded from the Diet.

Dilution of local voices

Due to the reduction in the number of seats, seats in local electoral districts may decrease further, potentially widening the gap with urban areas. For residents in sparsely populated areas, the means to convey their voices to national politics will become even more limited.

This is closely related to the aforementioned issue of the 'disparity in the value of a vote,' and could lead to a dual challenge of declining political influence for residents in sparsely populated areas.

Decline in the expertise of Diet members

When the number of Diet members decreases, individual members are forced to hold multiple committee positions simultaneously, making it difficult to enhance their expertise. It becomes harder to cultivate members with deep knowledge of policies in various fields.

Barriers to entry for newcomers, the younger generation, and women

As the number of seats decreases, the advantages of incumbent members increase, potentially making it even harder for newcomers, the younger generation, and women to enter the political arena. This not only impairs political diversity but also hinders generational change and the introduction of new perspectives.

In the Japanese Diet, where there is already no retirement age for members, such opportunities for renewal may decrease even further.

Decline in parliamentary functions

There is a concern that opportunities for questioning and inquiries will decrease, making it impossible for the Diet to fully fulfill its role. There is a risk that the original functions of the Diet, such as monitoring the administration and deliberating on bills, will be weakened.

Up to this point, we have examined the reality of the number of legislators in Japan based on data and looked in detail at the pros and cons of reducing the number of parliamentary seats.

It has become clear that in international comparisons, the number of Japanese legislators is by no means high, the economic effects are limited, and on the other hand, there are concerns such as the risk of losing the diversity of public opinion and local voices, as well as a decline in parliamentary functions.

So, what is the truly necessary political reform other than reducing the number of parliamentary seats? Did the 'reduction of parliamentary seats' actually carried out in Osaka really benefit the residents?

And isn't the issue of 'politics and money' the challenge that should be addressed with the highest priority? In the next installment (Part 3, Conclusion), we will consider what truly necessary reform looks like and explore what each of us should be asking.

[Reference Articles and Literature]

(*1) LDP and Ishin seek common ground for coalition; gaps remain on corporate donation regulations, social security reform faces a difficult path

(*2) Nomura Research Institute, 'Nippon Ishin no Kai's 12-point demand in coalition negotiations with the LDP' (October 2025)

(*3) Ishin's coalition-first approach swaps 'conditions'; corporate donation regulations left behind? Komeito pushes back on seat reduction [Deep Dive]

(*4) 'An electoral system to save the LDP': 4 lawyers file suit calling July's Upper House election 'unconstitutional and invalid'; courts have sought corrections in the past, but... the Diet's inaction in 'ignoring' the rulings

(*5) Noritoshi Furuichi's reason for thinking 'there are indeed too many national legislators': 'Looking at Japan's current national legislators...' (Sports Nippon)

Is reducing parliamentary seats counterproductive? Team Mirai leader Mr. Anno points out concerns: 'What is lost most is the metabolism of politicians'

The idea that reducing parliamentary seats reduces waste is wrong! Surprising results proven by economics; it actually leaves the wastefulness of bureaucrats and officials unchecked

• TechGym 'Complete Guide to the History of Parliamentary Seat Reduction'

• Statistics Bureau of Japan 'Population Census' annual editions

• GLOBAL NOTE 'World Ranking of Number of National Legislators by Country'

• House of Councillors Standing Committee Research Office 'On the Size of Parliament: A Comparison Among OECD Countries' (2021)

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