The is the upper house of the National Diet of Japan. The House of Representatives is the lower house. The Senate is the successor to the pre-war House of Peers. If the two houses disagree on matters of the budget, treaties, or the nomination of the prime minister, the House of Representatives can insist on its decision. In other decisions, the House of Representatives can override a vote of the Senate only by a two-thirds majority of senators present.
The Senate has 267 members who each serve six-year terms, two years longer than those of the House of Representatives. Senators must be at least 30 years old, compared with 25 years old in the House of Representatives. The Senate cannot be dissolved, and terms are staggered so that only half of its membership is up for election every three years. Of the 124 senators subject to election each time, 74 are elected from 45 districts by single non-transferable vote (SNTV) and 50 are elected from a nationwide list by proportional representation (PR) with open lists.Hayes 2009, p. 50
The English translation of the institution's name was established in 1946. In 2026 the official translation is planned to be changed to 'Senate', a name which already enjoyed some informal use before, to prevent international confusion, as the term "Councillor" is rarely used for national-level upper houses and more frequently associated with local government.
Roles and responsibilities
The power of the Senate is very similar to the Canadian Senate or the Irish Seanad. In central issues, there is a . In the election of the prime minister, the ratification of international treaties, and on passing the budget, a decision by the House of Representatives always overrides dissent from the Senate. Only the lower house can pass votes of no-confidence against the cabinet. All other legislation requires either the approval by majorities in both houses, an agreement in the conference committee of both houses or an additional override vote by two-thirds majority in the House of Representatives.House of Representatives: Diet functions: Diagram of (the) Legislative Procedure Thies M.F., Yanai Y. (2013) Governance with a Twist: How Bicameralism Affects Japanese Lawmaking. In: Pekkanen R., Reed S.R., Scheiner E. (eds) Japan Decides 2012. Palgrave Macmillan, London. (For context, no single party achieved a two-thirds majority in the House of Representatives until the Liberal Democratic Party did in the February 2026 election.) Usually, controlling a majority in the Senate and one third of the House of Representatives is enough for a united opposition to be able to block the passage of legislation. For certain important administrative nominations by the cabinet, the approval of both houses is required (although the laws containing this requirement could be changed by two-thirds lower house override as a "nuclear option"); and constitutional amendment proposals need two-thirds majorities in both houses of the Diet to be submitted to the people in a national referendum.
One additional constitutional role of the Senate is to serve as functioning fully elected emergency legislature on its own during lower house election campaigns: While the House of Representatives is dissolved, the National Diet can not be convened, and therefore no law can be passed in regular procedure; but in urgent cases requiring parliamentary action (e.g. election management, provisional budgets, disaster response), an of the Senate can still be invoked to take provisional decisions for the whole Diet. Such decisions will become invalid unless confirmed by the House of Representatives as soon as the whole Diet convenes again.
The basic stipulations on the role of the Senate are subject of chapter IV of the constitution.Text (in unreformed script) and English translation , Wikisource Laws and rules containing more detailed provisions on parliamentary procedures and the relations between the two houses include the ,Text and English translation , House of Councillors the ,Text , House of Councillors and the .HC rules: Text and English translation , House of Councillors; HR rules: Text , House of Representatives.
Constitutional practice In practice, governments often tried to ensure legislative majorities, either by forming coalition governments with safe legislative majorities in the first place or by negotiating with part of the opposition, or avoided to submit bills with no prospects of passage,Thies M.F., Yanai Y. (2014): Bicameralism vs. Parliamentarism: Lessons from Japan's Twisted Diet, Journal of Electoral Studies 30 (2), 60-74. (J-STAGE ) so the Senate rarely voted against the decisions reached by the lower house for much of postwar history: As the Liberal Democratic Party (LDP), founded in 1955, often held majorities in both houses or was sufficiently close to control both houses together with independents and micro-parties for a long period, inter-chamber disagreement was rare during most of the 1955 System.
After the opposition victory in the 1989 election, the relative importance of the Senate initially increased, as the LDP continued to govern alone and did not hold a two-thirds majority in the House of Representatives. Crucial legislation had to be negotiated with parts of the opposition. The most prominent example was the so-called of 1992 when the LDP negotiated and passed the peace-keeping operations bill with centre-left/right-of-JSP opposition parties (DSP and Kōmeitō) against fierce opposition from JSP and JCP; the Peace-Keeping Operations law (PKO law) became the base for the Self-Defense Forces' first ground deployment abroad as part of the UN mission in Cambodia. After the 1993 House of Representatives election, with the exception of a brief minority government in 1994, coalition governments or the confidence and supply arrangement during the restored LDP single-party government ensured legislative government majorities until the opposition victory in the 1998 Senate election which led to the formation of another coalition government by 1999.
The legislative two-thirds override power of the House of Representatives was never used between 1950s and 2008 when the LDP-Kōmeitō coalition government had lost the Senate majority in the 2007 election, but did control a two-thirds majority in the House of Representatives since 2005. After that, it has been used somewhat more frequently (see , , "Override decisions by the House of Representatives" for a list). If a government controls a two-thirds majority in the House of Representatives and is willing to use it, the Senate can only delay a bill, but not prevent passage.
Opposition control of the Senate is often summarized by the term . Setting aside the immediate postwar years, when many governments were in the minority in the upper house, but the strongest force, the centrist Ryokufūkai, was not in all-out opposition to either centre-left or centre-right governments and willing to cooperate, the Diet was "twisted" from 1989 to 1993, 1998–1999, 2007–2009, and most recently 2010–2013.
"Gridlock" and reform proposals In recent years, many constitutional revision advocates call for reforming the role of the Senate ("carbon copy" of the House of Representatives or "recalcitrant naysayer") or abolishing it altogether to "prevent political paralysis", after the recently more frequent twisted Diets have seen an increase in inter-chamber friction/"political nightmare"s.Takenaka Harukata, July 20, 2011: Why Japanese Politics Is at a Standstill , nippon.com (Nippon Foundation), retrieved September 12, 2021. Examples of high-stakes, internationally noted conflicts in recent twisted Diets: In 2008, two nominees for BoJ governor by the Fukuda Cabinet (Toshirō Mutō, Kōji Tanami) were rejected by the DPJ-led opposition in the Senate, and the SDF naval support mission for NATO/OEF in the Indian Ocean had to be interrupted for one month while the extension of the anti-terrorism law was delayed by the extended legislative proceedings necessary to override the Senate rejection. In 2011, the Kan Cabinet struggled to pass a renewable energy bill and a bond ceiling increase (unlike the budget itself subject to the normal legislative procedure) against the LDP-led opposition majority in the Senate until it negotiated a deal with the LDP in exchange for child allowance reform and the cabinet's resignation which Kan had already announced, but conditioned on the passage of the bills.Risa Maeda, Shinichi Saoshiro, Reuters, July 5, 2011: Japan opposition sets conditions for energy bill , retrieved September 12, 2021.Hiroko Tabuchi, The New York Times, August 23, 2011: Japan's Prime Minister Likely to Resign, Minister Says , retrieved September 12, 2021.
Membership and elections
Article 102 of the Japanese Constitution provided that half of the councillors elected in the first Senate election in 1947 would be up for re-election three years later in order to introduce staggered six-year terms.
The House initially had 250 seats. Two seats were added to the House in 1970 after the agreement on the repatriation of Okinawa, increasing the House to a total of 252. Legislation aimed at addressing malapportionment that favoured less populated prefectures was introduced in 2000; this resulted in ten seats being removed (five each at the 2001 and 2004 elections), bringing the total number of seats to 242. Further reforms to address malapportionment took effect in 2007 and 2016, but did not change the total number of members in the house.
From 1947 to 1983, the House had 100 seats allocated to a nationwide district, of which fifty seats were allocated in each election, elected by single non-transferable vote. It was originally intended to give nationally prominent figures a route to the House without going through local electioneering processes. Some national political figures, such as feminists Shidzue Katō and Fusae Ichikawa and former Imperial Army general Kazushige Ugaki, were elected through the nationwide district, along with a number of celebrities such as comedian Yukio Aoshima (later Governor of Tokyo), journalist Hideo Den and actress Yūko Mochizuki. Shintaro Ishihara won a record 3 million votes in the nationwide district in the 1968 election. The last 50-seat SNTV election took place in 1980. For the 1983 election the electoral system was changed to closed-list proportional representation; to avoid ambiguity, the nationwide district was now called the proportional district. The national proportional representation district was reduced to 96 senators in the 2000 reforms.
Current composition
Latest election
List of Senate regular elections 20th century ElectionCabinetPrime MinisterDateTurnoutTotalseatsElectedseatsTermexpirationdateMajority party / Seats shareEmperor1stYoshida IShigeru Yoshida20 April 194761.12%2502502 May 1953 Socialist4718.80% 2ndYoshida III4 June 195072.19%1253 June 1956 Liberal7630.40%3rdYoshida IV24 April 195363.18%2 May 19599337.20%4thI. Hatoyama IIIIchirō Hatoyama8 July 195662.11%7 July 1962 Liberal Democratic12248.80%5thKishi IINobusuke Kishi2 June 195958.75%1 June 196513252.80%6thIkeda IIHayato Ikeda1 July 196268.22%7 July 196814256.80%7thSatō IEisaku Satō4 July 196567.02%1 July 197114055.77%8thSatō II7 July 196868.94%7 July 197414254.80%9thSatō III27 June 197159.24%25212610 July 197713152.61%10thK. Tanaka IIKakuei Tanaka7 July 197473.20%7 July 198012650.40%11thT. FukudaTakeo Fukuda10 July 197768.49%9 July 198312449.79%12thŌhira IIMasayoshi Ōhira22 June 198074.54%7 July 198613554.00%13thNakasone IYasuhiro Nakasone26 June 198357.00%9 July 198913754.36%14thNakasone II (R2)6 July 198671.36%7 July 199214356.74%15thUnoSōsuke Uno23 July 198965.02%25212622 July 199510943.25% Akihito(Heisei)16thMiyazawaKiichi Miyazawa26 July 199250.72%25 July 199810742.46%17thMurayamaTomiichi Murayama23 July 199544.52%22 July 200111144.04%18thHashimoto II (R)Ryutaro Hashimoto12 July 199858.84%25 July 200410340.87%
21st century