National Diet of Japan 国会 Kokkai
215th Session of the National Diet
Type
Type	Bicameral
Houses	House of Councillors (upper house) House of Representatives (lower house)
Leadership
President of the House of Councillors	Masakazu Sekiguchi, LDP since 11 November 2024
Speaker of the House of Representatives	Fukushiro Nukaga, LDP since 11 November 2024
Prime Minister	Shigeru Ishiba, LDP since 1 October 2024
Structure
Seats	713 248 (House of Councillors) 465 (House of Representatives)
House of Councillors political groups	Government (140)   LDP (113)   Kōmeitō (27) Opposition (92)   CDP-SDP (42)[a]   Ishin (18)   DPFP-SR (11)[b]   JCP (11)   Reiwa (5)   NHK (2)[c]   Okinawa Social Mass Party (2) Unaffiliated (9)   Sanseitō (1)   Independent (8)[d] Vacant (8)   Vacant (8)
House of Representatives political groups	Government (221)   LDP (197)[e]   Kōmeitō (24) Opposition (242)   CDP (149)[f]   Ishin (38)   DPFP (28)   Reiwa (9)   JCP (8)   Yūshi no Kai (4)[g]   Sanseitō (3)   CPJ (3) Unaffiliated (2)   Independent (2)[h]
Elections
House of Councillors voting system	Parallel voting: Single non-transferable vote (147 seats) Party-list proportional representation (98 seats) Staggered elections
House of Representatives voting system	Parallel voting: First-past-the-post voting (289 seats) Party-list proportional representation (176 seats)
Last House of Councillors election	10 July 2022 (26th)
Last House of Representatives election	27 October 2024 (50th)
Next House of Councillors election	Before 25 July 2025 (27th)
Next House of Representatives election	No later than 22 October 2028 (51th)
Meeting place
National Diet Building, Nagatachō 1-7-1, Chiyoda District, Tokyo, Japan 35°40′33″N 139°44′42″E / 35.67583°N 139.74500°E / 35.67583; 139.74500
Website
House of Councillors – official website House of Representatives – official website

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The National Diet (Japanese: 国会, Hepburn: Kokkai) is the national legislature of Japan. It is composed of a lower house, called the House of Representatives (衆議院, Shūgiin), and an upper house, the House of Councillors (参議院, Sangiin). 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 (国会議事堂, Kokkai-gijidō) in Nagatachō, Chiyoda, Tokyo.

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 also 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.^[1][2] Japan's parallel voting system (mixed-member majoritarian) 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 insists that the electoral law must not discriminate in terms of "race, creed, sex, social status, family origin, education, property or income".^[3]

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 were relocating to the urban centers in the seeking of wealth; 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.^[4] 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.^[5] In recent elections the malapportionment ratio amounted to 4.8 in the House of Councillors (census 2005: Ōsaka/Tottori;^[6] election 2007: Kanagawa/Tottori^[7]) and 2.3 in the House of Representatives (election 2009: Chiba 4/Kōchi 3).^[8]

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, free Shinkansen tickets, and four round-trip airplane tickets a month to enable them to travel back and forth to their home districts.^[9]

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" (Article 62).

The Prime Minister must be designated by Diet resolution, establishing the principle of legislative supremacy over executive government agencies (Article 67). 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.^[3]

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.^[10]

The House of Representatives is the more powerful chamber of the Diet.^[11] 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:^[12]

• 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.^[13]
• 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.^[13]
• 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.

• National Diet Building Interior
• 
  House of Representatives
• 
  House of Councillors
• 
  The waiting room adjacent to the Cabinet Room at the National Diet Building

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.^[14] At the beginning of each parliamentary session, the Emperor reads a special speech from his throne in the chamber of the House of Councillors.^[15]

The presence of one-third of the membership of either house constitutes a quorum^[14] 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.^[16][17] 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.^[18]

The vast majority of bills are submitted to the Diet by the Cabinet.^[19] 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.^[20] Such advisory committees may include university professors, trade union representatives, industry representatives, and local governors and mayors, and invariably include retired officials.^[19] Such draft bills would be sent to the Cabinet Legislation Bureau of the government, as well as to the ruling party.^[19]

Japan's first modern legislature was the Imperial Diet (帝国議会, Teikoku-gikai) 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.^[21] 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 (albeit with a strong military). 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.^[22]

The Imperial Diet consisted of a House of Representatives and a House of Peers (貴族院, Kizoku-in). 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.^[23] The House of Peers, much like the British House of Lords, consisted of high-ranking nobles chosen by the Emperor.^[24]

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.^[25]

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.^[26] 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.^[27]

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.^[24] 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.^[28]

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.^[29] 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 (now Social Democratic Party), which in fact had sponsored the reform.^[30]

• National Diet buildings
• 
  The First Japanese Diet Hall (1890–91)
• 
  National Diet Hiroshima Temporary Building (1894)
• 
  The Second Japanese Diet Hall (1891–1925)
• 
  National Diet Building (1930)
• 
  National Diet Building (2017)

There are three types of sessions of the National Diet:^[31]

• R – jōkai (常会), regular, annual sessions of the National Diet, often shortened to "regular National Diet" (通常国会, tsūjō Kokkai). These are nowadays usually called in January, they last for 150 days and can be extended once.
• E – rinjikai (臨時会), extraordinary sessions of the National Diet, often shortened to "extraordinary National Diet" (臨時国会, rinji Kokkai). These are often called in autumn, or in the summer after a regular election of the House of Councillors (参議院議員通常選挙, sangiingiin tsūjōsenkyo) or after a full-term general election of the House of Representatives (衆議院議員総選挙, shūgiingiin sōsenkyo). Its length is negotiated between the two houses, it can be extended twice.
• S – tokubetsukai (特別会), special sessions of the National Diet, often shortened to "special National Diet" (特別国会, tokubetsu Kokkai). 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 (but inversely, not all PM elections take place in a special Diet). 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 (緊急集会, kinkyū shūkai) 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.^[32]

Any session of the National Diet may be cut short by a dissolution of the House of Representatives (衆議院解散, shūgiin kaisan). In the table, this is listed simply as "(dissolution)"; the House of Councillors or the National Diet as such cannot be dissolved.

Election	Date	Elected prime minister (during term)	Turnout	Seats	Date of dissolution (D) / expiration of term (E)	Registered voters	Majority party	Seats Share		Monarch (Reign)
Imperial Diet (1890–1947); upper house: House of Peers										Emperor Meiji (1867–1912)
1890	1 July 1890	Yamagata Aritomo	93.91%	300		450,872	Constitutional Liberal	130	43.33%
		(Matsukata Masayoshi)
1892	15 February 1892	Matsukata Masayoshi	91.59%		(D) December 25, 1891	434,594		094	31.33%
		(Itō Hirobumi)
Mar. 1894	March 1, 1894	Itō Hirobumi	88.76%		(D) December 30, 1893	440,113		120	40.00%
Sep. 1894	1 September 1894	Itō Hirobumi	84.84%		(D) June 2, 1894	460,483		107	35.66%
		(Matsukata Masayoshi)
		(Itō Hirobumi)
Mar. 1898	15 March 1898	Itō Hirobumi	87.50%		(D) December 25, 1897	452,637		105	35.00%
		(Ōkuma Shigenobu)
Aug. 1898	10 August 1898	Ōkuma Shigenobu	79.91%		(D) June 10, 1898	502,292	Kensei Hontō	124	41.33%
		(Yamagata Aritomo)
		(Itō Hirobumi)
		(Katsura Tarō)
Election	Date	Elected prime minister (during term)	Turnout	Seats	Date of dissolution (D) / expiration of term (E)	Registered voters	Majority party	Seats Share		Monarch (Reign)

Election	Date	Elected prime minister (during term)	Turnout	Seats	Date of dissolution (D) / expiration of term (E)	Registered voters	Majority party	Seats Share		Monarch (Reign)
1902	August 10, 1902	Katsura Tarō	88.39%	376	(E) August 9, 1902	982,868	Rikken Seiyūkai	191	50.79%	Emperor Meiji (1867–1912)
1903	March 1, 1903		86.17%		(D) December 28, 1902	958,322		175	46.54%
1904	1 March 1904	Katsura Tarō	86.06%	379	(D) December 11, 1903	762,445		133	35.09%
		(Saionji Kinmochi)
1908	15 May 1908	Saionji Kinmochi	85.29%		(E) March 27, 1908	1,590,045		187	49.34%
		(Katsura Tarō)
		(Saionji Kinmochi)
1912	15 May 1912	Saionji Kinmochi	89.58%	381	(E) May 14, 1912	1,506,143		209	54.85%
		(Katsura Tarō)
		(Yamamoto Gonnohyōe)
		(Ōkuma Shigenobu)
1915	25 March 1915	Ōkuma Shigenobu	92.13%		(D) December 25, 1914	1,546,411	Rikken Dōshikai	153	40.15%	Emperor Taishō (1912–1926)
		(Terauchi Masatake)
1917	20 April 1917	Terauchi Masatake	91.92%		(D) January 25, 1917	1,422,126	Rikken Seiyūkai	165	43.30%
		(Hara Takashi)
1920	10 May 1920	Hara Takashi	86.73%	464	(D) February 26, 1920	3,069,148		278	59.91%
		(Takahashi Korekiyo)
		(Katō Tomosaburō)
		(Yamamoto Gonnohyōe)
		(Kiyoura Keigo)
1924	10 May 1924	Katō Takaaki	91.18%		(D) January 31, 1924	3,288,405	Kenseikai	151	32.54%
		(Wakatsuki Reijirō)
		(Tanaka Giichi)
1928	20 February 1928	Tanaka Giichi	80.36%	466	(D) January 21, 1928	12,408,678	Rikken Seiyūkai	218	46.78%	Emperor Shōwa (1926–1989)
		(Hamaguchi Osachi)
1930	20 February 1930	Hamaguchi Osachi	83.34%		(D) January 21, 1930	12,812,895	Rikken Minseitō	273	58.58%
		(Wakatsuki Reijirō)
		(Inukai Tsuyoshi)
1932	20 February 1932	Inukai Tsuyoshi	81.68%		(D) January 21, 1932	13,237,841	Rikken Seiyukai	301	64.59%
		(Saitō Makoto)
		(Keisuke Okada)
1936	20 February 1936	Kōki Hirota	78.65%		(D) January 21, 1936	14,479,553	Rikken Minseitō	205	43.99%
		(Senjūrō Hayashi)
1937	30 April 1937	Senjūrō Hayashi	73.31%		(D) March 31, 1937	14,618,298		179	38.41%
		(Fumimaro Konoe)
		(Hiranuma Kiichirō)
		(Nobuyuki Abe)
		(Mitsumasa Yonai)
		(Fumimaro Konoe)
		(Fumimaro Konoe)
		(Hideki Tojo)
1942	30 April 1942	Hideki Tojo	83.16%		(E) April 29, 1942	14,594,287	Imperial Rule Assistance Association	381	81.75%
		(Kuniaki Koiso)
		(Kantarō Suzuki)
		(Kantarō Suzuki)
		(Prince Naruhiko Higashikuni)
		(Kijūrō Shidehara)
1946	April 10, 1946	Shigeru Yoshida	72.08%		(D) December 18, 1945	36,878,420	Liberal	141	30.25%
1947	25 April 1947	Tetsu Katayama	67.95%		(D) March 31, 1947	40,907,493	Socialist	143	30.68%
		(Hitoshi Ashida)
		(Shigeru Yoshida)
National Diet (1947–present); upper house: House of Councillors
1949	23 January 1949	Shigeru Yoshida	74.04%	466	(D) December 23, 1948	42,105,300	Democratic Liberal	264	56.65%
		(Shigeru Yoshida)
1952	October 1, 1952	Shigeru Yoshida	76.43%		(D) August 28, 1952	46,772,584	Liberal	240	51.50%
1953	19 April 1953	Shigeru Yoshida	74.22%		(D) March 14, 1953	47,090,167	Liberal Yoshida faction	199	42.70%
		(Ichirō Hatoyama)
1955	27 February 1955	Ichirō Hatoyama	75.84%	467	(D) January 24, 1955	49,235,375	Democratic	185	39.61%
		(Ichirō Hatoyama)
		(Tanzan Ishibashi)
		(Nobusuke Kishi)
1958	22 May 1958	Nobusuke Kishi	76.99%		(D) April 25, 1958	52,013,529	Liberal Democratic	287	61.45%
		(Hayato Ikeda)
1960	November 20, 1960	Hayato Ikeda	73.51%		(D) October 24, 1960	54,312,993		296	63.38%
1963	21 November 1963	Hayato Ikeda	71.14%		(D) October 23, 1963	58,281,678		283	60.59%
		(Eisaku Satō)
1967	January 29, 1967	Eisaku Satō	73.99%	486	(D) December 27, 1966	62,992,796		277	56.99%
1969	27 December 1969	Eisaku Satō	68.51%		(D) December 2, 1969	69,260,424		288	59.25%
		(Kakuei Tanaka)
1972	10 December 1972	Kakuei Tanaka	71.76%	491	(D) November 13, 1972	73,769,636		271	55.19%
		(Takeo Miki)
1976	5 December 1976	Takeo Fukuda	73.45%	511	(E) December 9, 1976	77,926,588		249	48.72%
		(Masayoshi Ōhira)
1979	October 7, 1979	Masayoshi Ōhira	68.01%		(D) September 7, 1979	80,169,924		248	48.53%
1980	22 June 1980	Zenkō Suzuki	74.57%		(D) May 19, 1980	80,925,034		284	55.57%
		(Yasuhiro Nakasone)
1983	December 18, 1983	Yasuhiro Nakasone	67.94%		(D) November 28, 1983	84,252,608	Liberal Democratic (LDP-NLC coalition)	250	48.92%
1986	2 June 1986	Yasuhiro Nakasone	71.40%	512	(D) June 2, 1986	86,426,845	Liberal Democratic	300	58.59%
		(Noboru Takeshita)
		(Sōsuke Uno)
		(Toshiki Kaifu)
1990	18 February 1990	Toshiki Kaifu	73.31%		(D) January 24, 1990	90,322,908		275	53.71%	Emperor Akihito (Heisei) (1989–2019)
		(Kiichi Miyazawa)
1993	18 July 1993	Morihiro Hosokawa	67.26%	511	(D) June 18, 1993	94,477,816	Liberal Democratic (JNP-JRP–JSP-Komeito–DSP-NPS-SDF coalition: 1993–1994, JRP–Komeito–JNP-DSP-Liberal Reform League coalition: 1994, LDP-JSP-NPS coalition since 1994)	223	43.63%
		(Tsutomu Hata)
		(Tomiichi Murayama)
		(Ryūtarō Hashimoto)
1996	20 October 1996	Ryūtarō Hashimoto	59.65%	500	(D) September 27, 1996	97,680,719	Liberal Democratic (LDP-JSP/SDP-NPS coalition: 1996, LDP-Liberal coalition: 1999, LDP-Komeito-Liberal/NCP coalition: 1999–2000, LDP-Komeito-NCP coalition: 2000)	239	47.80%
		(Keizō Obuchi)
		(Yoshirō Mori)
2000	25 June 2000	Yoshirō Mori	62.49%	480	(D) June 2, 2000	100,492,328	Liberal Democratic (LDP-Komeito-NCP coalition)	233	48.54%
		(Junichiro Koizumi)
Election	Date	Elected prime minister (during term)	Turnout	Seats	Date of dissolution (D) / expiration of term (E)	Registered voters	Majority party	Seats Share		Monarch (Reign)

Election	Date	Elected prime minister (during term)	Turnout	Seats	Date of dissolution (D) / expiration of term (E)	Registered voters	Majority party	Seats Share		Monarch (Reign)
2003	November 9, 2003	Junichiro Koizumi	59.86%	480	(D) October 10, 2003	102,306,684	Liberal Democratic (LDP-Komeito coalition)	237	49.37%	Emperor Akihito (Heisei) (1989–2019)
2005	11 September 2005	Junichiro Koizumi	67.51%		(D) August 8, 2005	103,067,966		296	61.66%
		(Shinzo Abe)
		(Yasuo Fukuda)
		(Tarō Asō)
2009	30 August 2009	Yukio Hatoyama	69.28%		(D) July 21, 2009	104,057,361	Democratic (DPJ-PNP-SDP coalition: 2009–2010, DPJ-PNP coalition: 2010–2012)	308	64.16%
		(Naoto Kan)
		(Yoshihiko Noda)
2012	December 16, 2012	Shinzo Abe	59.32%		(D) November 16, 2012	103,959,866	Liberal Democratic (LDP-Komeito coalition)	294	61.25%
2014	December 14, 2014		52.66%	475	(D) November 21, 2014	104,067,104		291	61.26%
2017	22 October 2017	Shinzo Abe	53.68%	465	(D) September 28, 2017	106,091,229		284	61.08%
		(Yoshihide Suga)
		(Fumio Kishida)
2021	October 31, 2021	Fumio Kishida	55.93%		(D) October 14, 2021	105,622,758		261	56.12%	Emperor Naruhito (Reiwa) (2019–present)
Election	Date	Elected prime minister (during term)	Turnout	Seats	Date of dissolution (D) / expiration of term (E)	Registered voters	Majority party	Seats Share		Monarch (Reign)

• 1947 Japanese House of Councillors election
• 1950 Japanese House of Councillors election
• 1953 Japanese House of Councillors election
• 1956 Japanese House of Councillors election
• 1959 Japanese House of Councillors election
• 1962 Japanese House of Councillors election
• 1965 Japanese House of Councillors election
• 1968 Japanese House of Councillors election
• 1971 Japanese House of Councillors election
• 1974 Japanese House of Councillors election
• 1977 Japanese House of Councillors election
• 1980 Japanese House of Councillors election
• 1983 Japanese House of Councillors election
• 1986 Japanese House of Councillors election
• 1989 Japanese House of Councillors election
• 1992 Japanese House of Councillors election
• 1995 Japanese House of Councillors election
• 1998 Japanese House of Councillors election

• 2001 Japanese House of Councillors election
• 2004 Japanese House of Councillors election
• 2007 Japanese House of Councillors election
• 2010 Japanese House of Councillors election
• 2013 Japanese House of Councillors election
• 2016 Japanese House of Councillors election
• 2019 Japanese House of Councillors election
• 2022 Japanese House of Councillors election

• Bicameralism
• Diet (assembly)
• Government of Japan
• History of Japan
• List of legislatures by country
• List of members of the Diet of Japan
• National Diet Building
• National Diet Library
• Parliamentary system
• Politics of Japan
• ja:国会開会式 – Opening ceremony of National Diet

Wikimedia Commons has media related to Diet of Japan.

• National Diet Library: Diet and Parliaments has the Diet minutes and additional information (in Japanese) (archived 18 October 2002)