National Diet


The National Diet is the national legislature of Japan. It is composed of a lower house, called the House of Representatives, and an upper house, the House of Councillors. Both houses are directly elected under a parallel voting system. In addition to passing laws, the Diet is formally responsible for nominating the prime minister. The Diet was first established as the Imperial Diet in 1890 under the Meiji Constitution, and took its current form in 1947 upon the adoption of the post-war constitution. Both houses meet in the National Diet Building in Nagatachō, Chiyoda, Tokyo.

Composition

The houses of the National Diet are both elected under parallel voting systems. This means that the seats to be filled in any given election are divided into two groups, each elected by a different method; the main difference between the houses is in the sizes of the two groups and how they are elected. Voters are asked to cast two votes: one for an individual candidate in a constituency, and one for a party list. Any national of Japan at least 18 years of age may vote in these elections, reduced from age 20 in 2016. Japan's parallel voting system is not to be confused with the mixed-member proportional systems used in many other nations. The Constitution of Japan does not specify the number of members of each house of the Diet, the voting system, or the necessary qualifications of those who may vote or be returned in parliamentary elections, thus allowing all of these things to be determined by law. However it does guarantee universal adult suffrage and a secret ballot. It also stipulates that the electoral law must not discriminate in terms of "race, creed, sex, social status, family origin, education, property or income".
Generally, the election of Diet members is controlled by statutes passed by the Diet. This is a source of contention concerning re-apportionment of prefectures' seats in response to changes of population distribution. For example, the Liberal Democratic Party had controlled Japan for most of its post-war history, and it gained much of its support from rural areas. During the post-war era, large numbers of people relocated to urban centers for economic reasons; though some re-apportionments have been made to the number of each prefecture's assigned seats in the Diet, rural areas generally have more representation than do urban areas. Among rural interests, Japanese rice farmers historically had particular influence in internal LDP politics and national policies on trade and agricultural subsidies.
The Supreme Court of Japan began exercising judicial review of apportionment laws following the Kurokawa decision of 1976, invalidating an election in which one district in Hyōgo Prefecture received five times the representation of another district in Osaka Prefecture. In the most recent elections, the malapportionment ratio amounted to 3.03 in the House of Councillors and 2.06 in the House of Representatives.
Candidates for the lower house must be 25 years old or older and 30 years or older for the upper house. All candidates must be Japanese nationals. Under Article 49 of Japan's Constitution, Diet members are paid about ¥1.3 million a month in salary. Each lawmaker is entitled to employ three secretaries with taxpayer funds, and to receive free Shinkansen tickets, and four round-trip airplane tickets a month to enable them to travel back and forth to their home districts.

Powers

Article 41 of the Constitution describes the National Diet as "the highest organ of State power" and "the sole law-making organ of the State". This statement is in forceful contrast to the Meiji Constitution, which described the Emperor as the one who exercised legislative power with the consent of the Diet. The Diet's responsibilities include not only the making of laws but also the approval of the annual national budget that the government submits and the ratification of treaties. It can also initiate draft constitutional amendments, which, if approved, must be presented to the people in a referendum. The Diet may conduct "investigations in relation to government".
The Prime Minister must be designated by Diet resolution, establishing the principle of legislative supremacy over executive government agencies. The government can also be dissolved by the Diet if the House of Representatives passes a motion of no confidence introduced by fifty members of the House of Representatives. Government officials, including the Prime Minister and Cabinet members, are required to appear before Diet investigative committees and answer inquiries. The Diet also has the power to impeach judges convicted of criminal or irregular conduct.
In most circumstances, in order to become law a bill must be first passed by both houses of the Diet and then promulgated by the Emperor. This role of the Emperor is similar to the Royal Assent in some other nations; however, the Emperor cannot refuse to promulgate a law and therefore his legislative role is merely a formality.
The House of Representatives is the more powerful chamber of the Diet. While the House of Representatives cannot usually overrule the House of Councillors on a bill, the House of Councillors can only delay the adoption of a budget or a treaty that has been approved by the House of Representatives, and the House of Councillors has almost no power at all to prevent the lower house from selecting any Prime Minister it wishes. Furthermore, once appointed it is the confidence of the House of Representatives alone that the Prime Minister must enjoy in order to continue in office. The House of Representatives can overrule the upper house in the following circumstances:
  • If a bill is adopted by the House of Representatives and then either rejected, amended or not approved within 60 days by the House of Councillors, then the bill will become law if again adopted by the House of Representatives by a majority of at least two-thirds of members present.
  • If both houses cannot agree on a budget or a treaty, even through the appointment of a joint committee of the Diet, or if the House of Councillors fails to take final action on a proposed budget or treaty within 30 days of its approval by the House of Representatives, then the decision of the lower house is deemed to be that of the Diet.
  • If both houses cannot agree on a candidate for Prime Minister, even through a joint committee, or if the House of Councillors fails to designate a candidate within 10 days of House of Representatives' decision, then the nominee of the lower house is deemed to be that of the Diet.

    Activities

Under the Constitution, at least one session of the Diet must be convened each year. Technically, only the House of Representatives is dissolved before an election. But, while the lower house is in dissolution, the House of Councillors is usually "closed". The Emperor both convokes the Diet and dissolves the House of Representatives but in doing so must act on the advice of the Cabinet. In an emergency the Cabinet can convoke the Diet for an extraordinary session, and an extraordinary session may be requested by one-quarter of the members of either house. At the beginning of each parliamentary session, the Emperor reads a special speech from his throne in the chamber of the House of Councillors.
The presence of one-third of the membership of either house constitutes a quorum and deliberations are in public unless at least two-thirds of those present agree otherwise. Each house elects its own presiding officer who casts the deciding vote in the event of a tie. The Diet has parliamentary immunity. Members of each house have certain protections against arrest while the Diet is in session and arrested members must be released during the term of the session if the House demands. They are immune outside the house for words spoken and votes cast in the House. Each house of the Diet determines its own standing orders and has responsibility for disciplining its own members. A member may be expelled, but only by a two-thirds majority vote. Every member of the Cabinet has the right to appear in either house of the Diet for the purpose of speaking on bills, and each house has the right to compel the appearance of Cabinet members.

Legislative process

The vast majority of bills are submitted to the Diet by the Cabinet. Bills are usually drafted by the relevant ministry, sometimes with the advice of an external committee if the issue is sufficiently important or neutrality is necessary. Such advisory committees may include university professors, trade union representatives, industry representatives, and local governors and mayors, and invariably include retired officials. Such draft bills would be sent to the Cabinet Legislation Bureau of the government, as well as to the ruling party.

Building

History

Japan's first modern legislature was the Imperial Diet established by the Meiji Constitution in force from 1889 to 1947. The Meiji Constitution was adopted on February 11, 1889, and the Imperial Diet first met on November 29, 1890, when the document entered into force. The first Imperial Diet of 1890 was plagued by controversy and political tensions. The Prime Minister of Japan at that time was General Count Yamagata Aritomo, who entered into a confrontation with the legislative body over military funding. During this time, there were many critics of the army who derided the Meiji slogan of "rich country, strong military" as in effect producing a poor country. They advocated for infrastructure projects and lower taxes instead and felt their interests were not being served by high levels of military spending. As a result of these early conflicts, public opinion of politicians was not favorable.
The Imperial Diet consisted of a House of Representatives and a 'House of Peers. The House of Representatives was directly elected, if on a limited franchise; universal adult male suffrage was introduced in 1925 when the Universal Manhood Suffrage Law was passed, but excluded women, and was limited to men 25 years or older. The House of Peers, much like the British House of Lords, consisted of high-ranking nobles chosen by the Emperor.
The first election by universal suffrage without distinction of sex was held in 1946, but it was not until 1947, when the constitution for post-war Japan came into effect, that universal suffrage was established In Japan.
The word
diet derives from Latin and was a common name for an assembly in medieval European polities like the Holy Roman Empire. The Meiji Constitution was largely based on the form of constitutional monarchy found in nineteenth century Prussia that placed the king not as a servant of the state but rather the sole holder of power and sovereignty over his kingdom, which the Japanese view of their emperor and his role at the time favoured. The new Diet was modeled partly on the German Reichstag and partly on the British Westminster system. Unlike the post-war constitution, the Meiji constitution granted a real political role to the Emperor, although in practice the Emperor's powers were largely directed by a group of oligarchs called the genrō'' or elder statesmen.
To become law or bill, a constitutional amendment had to have the assent of both the Diet and the Emperor. This meant that while the Emperor could no longer legislate by decree he still had a veto over the Diet. The Emperor also had complete freedom in choosing the Prime Minister and the Cabinet, and so, under the Meiji Constitution, Prime Ministers often were not chosen from and did not enjoy the confidence of the Diet. The Imperial Diet was also limited in its control over the budget. However, the Diet could veto the annual budget. If no budget was approved, the budget of the previous year continued in force. This changed with the new constitution after World War II.
The proportional representation system for the House of Councillors, introduced in 1982, was the first major electoral reform under the post-war constitution. Instead of choosing national constituency candidates as individuals, as had previously been the case, voters cast ballots for parties. Individual councillors, listed officially by the parties before the election, are selected on the basis of the parties' proportions of the total national constituency vote. The system was introduced to reduce the excessive money spent by candidates for the national constituencies. Critics charged, however, that this new system benefited the two largest parties, the LDP and the Japan Socialist Party, which in fact had sponsored the reform. As a result of both the 2024 Japanese general election and the 2025 [Japanese House of Councillors election], the LDP for the first time in party history failed to control either of the two houses in the National Diet.

List of sessions

There are three types of sessions of the National Diet:
  • R –, regular, annual sessions of the National Diet, often called "regular National Diet". These are nowadays usually called in January, they last for 150 days and can be extended once.
  • E –, extraordinary sessions of the National Diet, often called "extraordinary National Diet". These are often called in autumn, or in the summer after a regular election of the House of Councillors or after a full-term general election of the House of Representatives. Its length is negotiated between the two houses, it can be extended twice.
  • S –, special sessions of the National Diet, often called "special National Diet". They are called only after a dissolution and early general election of the House of Representatives. Because the cabinet must resign after a House of Representatives election, the National Diet always chooses a prime minister-designate in a special session. A special session can be extended twice.
  • HCES – There is a fourth type of legislative session: If the House of Representatives is dissolved, a National Diet cannot be convened. In urgent cases, the cabinet may invoke an emergency session of the House of Councillors to take provisional decisions for the whole Diet. As soon as the whole National Diet convenes again, these decisions must be confirmed by the House of Representatives or become ineffective. Such emergency sessions have been called twice in history, in 1952 and 1953.
Any session of the National Diet may be cut short by a dissolution of the House of Representatives. In the table, this is listed simply as ""; the House of Councillors or the National Diet as such cannot be dissolved.
DietTypeOpenedClosedLength in days
1stS204
2ndR209
3rdE51
4thR
23
5thS110
6thE40
7thR150
8thE20
9thE19
10thR178
11thE3
12thE52
13thR225
14th R
3
15th S
142
16thS85
17thE10
18thE9
19thR188
20thE10
21stR
46
22ndS135
23rdE25
24thR167
25thE32
26thR151
27thE14
28thR
127
29thS29
30thE70
31stR144
32ndE12
33rdE63
34thR200
35thE5
36thE
8
37thS18
38thR165
39thE37
40thR150
41stE30
42ndE16
43rdR195
44thE
9
45thS15
46thR190
47thE40
48thR163
49thE21
50thE70
51stR190
52ndE20
53rdE21
54th R
1
55thS157
56thE23
57thE20
58thR160
59thE10
60thE12
61stR222
62ndE
4
63rdS120
64th E25
65thR150
66thE11
67thE73
68thR171
69thE7
70thE
18
71st S280
72ndR185
73rdE8
74thE17
75thR190
76thE106
77thR150
78thE50
79thE5
80thR162
81stE8
82ndE58
83rdE4
84thR180
85thE34
86thE7
87thR175
88thE
9
89thS18
90thE16
91stR
151
92ndS10
93rdE62
94thR167
95thE66
96th R244
97thE30
98thR150
99thE6
100thE
82
101stS227
102ndR207
103rdE69
104thR150
105th E
1
106thS4
107thE4
108thR150
109thE76
110thE6
111thE16
112thR150
113thE163
114thR175
115thE6
116thE80
117thR
31
118thS120
119thE30
120thR150
121stE61
122ndE47
123rdR150
124thE5
125thE42
126thR
148
127thS24
128thE135
129thR150
130thE5
131stE71
132ndR150
133rdE5
134thE78
135thE3
136th R150
137thE
1
138thS6
139thE20
140thR150
141stE75
142ndR158
143rd E79
144thE18
145thR207
146thE48
147thR
135
148th S3
149thE13
150thE72
151stR150
152ndE4
153rdE72
154thR192
155thE57
156thR190
157thE
15
158thS9
159thR150
160thE8
161stE53
162ndR
200
163rd S42
164th R150
165th S85
166th R162
167th E4
168th E128
169th R156
170th E93
171st R
198
172nd S4
173rd E40
174th R150
175th E8
176th E64
177th R220
178th E18
179th E51
180th R229
181st E
19
182nd S3
183rd R150
184th E6
185th E55
186th R150
187th E
54
188th S3
189th R245
190th R150
191st E3
192nd E83
193rd R150
194th E
1
195th S39
196th R182
197th E48
198th R150
199th E5
200th E67
201st R150
202nd E3
203rd E41
204th R150
205th E
11
206th S3
207th E16
208th R150
209th E3
210th E69
211th R150
212th E55
213th R150
214th E
9
215th S4
216th E27
217th R150
218th E5
219th E58
220th R
1

List of House of Representatives general elections

19th century

20th century

21st century

List of House of Councillors regular elections

20th century

21st century