The is a

political party in Japan In Japan, any organization that supports a candidate needs to register itself as a political party. Each of these parties have some local or national influence. This article lists political parties in Japan with representation in the National Die ...

that was established in 1996. Since its reformation and name change in 1996, it has advocated

pacifism Pacifism is the opposition to war or violence. The word ''pacifism'' was coined by the French peace campaigner Émile Arnaud and adopted by other peace activists at the tenth Universal Peace Congress in Glasgow in 1901. A related term is ...

and defined itself as a

social-democratic Social democracy is a social, economic, and political philosophy within socialism that supports political and economic democracy and a gradualist, reformist, and democratic approach toward achieving social equality. In modern practice, socia ...

party. It was previously known as the . The party was re-founded in January 1996 by the majority of legislators of the former Japan Socialist Party, which was the largest opposition party in the 1955 System. However, most of those legislators joined the

Democratic Party of Japan The was a Centrism, centristThe Democratic Party of Japan was widely described as centrist: * * * * * * * to Centre-left politics, centre-left, Liberalism, liberal or Social liberalism, social-liberal List of political parties in Japan, ...

after that. Five leftist legislators who did not join the SDP formed the New Socialist Party, which lost all its seats in the following election. The SDP enjoyed a short period of government participation from 1993 to 1994 as part of the

Hosokawa Cabinet The Hosokawa Cabinet governed Japan from August 9, 1993, to April 28, 1994 under the premiership of Morihiro Hosokawa. In Japan, his administration is generally referred to as a representative example of non-LDP and non-JCP Coalition. Political ...

and later formed a coalition government with the

Liberal Democratic Party Several political parties from around the world have been called the Liberal Democratic Party, Democratic Liberal Party or Liberal Democrats. These parties have usually followed liberalism as ideology, although they can vary widely from very progr ...

under 81st

Prime Minister A prime minister or chief of cabinet is the head of the cabinet and the leader of the ministers in the executive branch of government, often in a parliamentary or semi-presidential system. A prime minister is not the head of state, but r ...

Tomiichi Murayama is a Japanese politician who served as Prime Minister of Japan from 1994 to 1996. He was the country's first socialist premier since Tetsu Katayama in 1948, and is best remembered for the Murayama Statement on the 50th anniversary of the end of ...

of the JSP from 1994 to January 1996. The SDP was part of ruling coalitions between January and November 1996 ( First Hashimoto Cabinet) and from 2009 to 2010 (

Hatoyama Cabinet The Yukio Hatoyama Cabinet governed Japan from September 2009 to June 2010, following the landslide victory of the Democratic Party of Japan in the general election on 30 August 2009. The election marked the first time in Japanese post-war histo ...

). In the

2019 Japanese House of Councillors election House of Councillors elections were held in Japan on 21 July 2019 to elect 124 of the 245 members of the upper house of the National Diet for a term of six years. 74 members were elected by single non-transferable vote (SNTV)/First-past-the-post ...

, the party won four representatives in the

National Diet , transcription_name = ''Kokkai'' , legislature = 215th Session of the National Diet , coa_pic = Flag of Japan.svg , house_type = Bicameral , houses = , foundation=29 November 1890(), leader1_type ...

, two in the lower house and two in the upper house. In November 2020, the party entered into a merger agreement with the

Constitutional Democratic Party The Constitutional Democratic Party (, K-D), also called Constitutional Democrats and formally the Party of People's Freedom (), was a political party in the Russian Empire that promoted Western constitutional monarchy—among other policies� ...

(CDP) with the SDP's members in the Diet caucusing with the CDP. The party president Mizuho Fukushima held her seat and, in the 2022 House of Councillors elections, the party cleared the minimum two percent voter share to maintain its legal political party status.

History

Before 2000

In 1995, the former Japan Socialist Party (JSP) was in a deep crisis, facing criticism for entering a coalition with its long-time rival, the LDP and for core policy changes. Aiming at saving the party, the leadership of JSP decided to dissolve the party and to establish a new social democratic party. In January 1996, a new party, the Social Democratic Party, was established, along with the dissolution of JSP. ''

De jure In law and government, ''de jure'' (; ; ) describes practices that are officially recognized by laws or other formal norms, regardless of whether the practice exists in reality. The phrase is often used in contrast with '' de facto'' ('from fa ...

'', JSP changed its name to the Social Democratic Party (SDP) as an interim party for forming a new party, and a movement for transforming the SDP into a new social-democratic and liberal party was unsuccessful. Under Murayama's successor

Ryūtarō Hashimoto was a Japanese politician who served as prime minister of Japan from 1996 to 1998. Born in Okayama Prefecture, Hashimoto graduated from Keio University in 1960 and entered the National Diet in 1963. He rose through the ranks of the Liberal Dem ...

(LDP), the SDP remained part of the ruling coalition. Long before its disappointing result in the

1996 Japanese general election General elections were held in Japan on 20 October 1996. A coalition of the Liberal Democratic Party (Japan), Liberal Democratic Party, New Party Sakigake and the Social Democratic Party (Japan), Social Democratic Party, led by incumbent Prime M ...

, the party lost the majority of its members of the House of Representatives, mainly to predecessors of the

(DPJ) that was formed in 1996, but also some to the NFP and other opposition parties. After its electoral defeat in the 1996 general election, when it lost another 15 of its remaining 30 seats in the lower house, the SDP left the ruling coalition, which it had entered as the second-largest force in Japanese politics, as a minor party.

2000s–2010s

The SDP won six seats in the

2003 Japanese general election General elections were held in Japan on November 9, 2003. Incumbent Prime Minister Junichiro Koizumi and the Liberal Democratic Party won the most seats in the House of Representatives but failed to secure a majority. The main opposition Democ ...

, compared with 18 seats in the previous

2000 Japanese general election General elections were held in Japan on 25 June 2000 to elect the 480 members of the House of Representatives. The ruling Liberal Democratic Party (LDP) remained the largest party in the House of Representatives but lost seats, along with its tw ...

. The party's opposition to the Self-Defense Forces reverted to the abolition of the forces in the long term, the policy it had in the 1950s. Doi had been the leader since 1996, but she resigned in 2003, taking responsibility for the election losses.

Mizuho Fukushima is a Japanese politician and attorney. A native of Nobeoka, Miyazaki, she has been a member of the House of Councillors (Japan), House of Councillors since 1998, was re-elected in 2004 and 2010, and was the head of the Social Democratic Party (J ...

was elected as the new party leader in November 2003. In the

2004 Japanese House of Councillors election House of Councillors elections were held in Japan on 11 July 2004. The House of Councillors consisted of 242 members who served six-year terms. Approximately half the members are elected every three years. At these elections 121 members were ele ...

, the SDP won only two seats, having five seats in the

House of Councillors The is the upper house of the National Diet of Japan. The House of Representatives (Japan), House of Representatives is the lower house. The House of Councillors is the successor to the pre-war House of Peers (Japan), House of Peers. If the t ...

and six seats in the

House of Representatives House of Representatives is the name of legislative bodies in many countries and sub-national entities. In many countries, the House of Representatives is the lower house of a bicameral legislature, with the corresponding upper house often ...

. In 2006, the party unexpectedly gained the governorship of the

Shiga Prefecture is a landlocked prefecture of Japan in the Kansai region of Honshu. Shiga Prefecture has a population of 1,398,972 as of 1 February 2025 and has a geographic area of . Shiga Prefecture borders Fukui Prefecture to the north, Gifu Prefecture to th ...

. In the

2009 Japanese general election General elections were held in Japan on August 30, 2009 to elect the 480 members of the House of Representatives. The opposition Democratic Party of Japan (DPJ) defeated the ruling coalition Liberal Democratic Party (LDP) and New Komeito Party ...

, the DPJ made large gains and the SDP maintained its base of 7 seats in the, becoming a junior partner in a new government coalition; however, disagreements over the issue of the Futenma base led to the sacking of Fukushima from the cabinet on 28 May and the SDP subsequently voted to leave the ruling coalition. Social Democratic Party of Japan - campaginvan - dec13-2012

Social Democratic Party of Japan - campaginvan - dec13-2012

As of October 2010, the SDP had six members in the House of Representatives and four members in the House of Councillors. Following the

2012 Japanese general election General elections were held in Japan on 16 December 2012. Voters gave the Liberal Democratic Party a landslide victory, ejecting the Democratic Party from power after three years. It was the fourth worst defeat suffered by a ruling party in J ...

, the party retained only six seats in the whole of the Diet, two in the House of Representatives and four in the House of Councillors. The count lowered to five seats in 2013. In 2013, the party's headquarters in Nagatacho, where the party's predecessor the JSP had moved in 1964, were demolished. The headquarters moved to a smaller office in Nagatacho. During the nomination period of the

2016 Japanese House of Councillors election House of Councillors elections were held in Japan on Sunday 10 July 2016 to elect 121 of the 242 members of the upper house of the National Diet, for a term of six years. As a result of the election, the Liberal Democratic Party– Komeito coali ...

, the party signed an agreement with the Democratic,

Communist Communism () is a sociopolitical, philosophical, and economic ideology within the socialist movement, whose goal is the creation of a communist society, a socioeconomic order centered on common ownership of the means of production, di ...

and People's Life parties to field a jointly-endorsed candidate in each of the 32 districts in which only one seat is contested, thereby uniting in an attempt to take control of the House from the LDP/

Komeito , formerly New Komeito (NKP) and commonly referred to as simply Komei, is a political party in Japan founded by the leader of Soka Gakkai, Daisaku Ikeda, in 1964. It is generally considered centrist and socially conservative. Since 2012, i ...

coalition. The party had two Councillors up for re-election and fielded a total of 11 candidates in the election, 4 in single and multi-member districts and 7 in the 48-seat national proportional representation block. In the

2017 Japanese general election General elections were held in Japan on 22 October 2017. Voting took place in all Representatives constituencies of Japan – 289 single-member districts and eleven proportional blocks – in order to appoint all 465 members (down from 475) of t ...

, the party managed to hold to its two seats it had prior to the election. Tadatomo Yoshida declined to run for re-election when his term expired in January 2018.

Seiji Mataichi was a Japanese politician who served as a member of the House of Councillors. He was also the Chairman of the Social Democratic Party. Mataichi died on 18 September 2023, at the age of 79. References External links Official websitein Japa ...

was elected unopposed in the ensuing leadership election and took office on 25 February 2018.

Since 2020

On 14 November 2020, the party voted to agree to a merger arrangement with the

Constitutional Democratic Party of Japan The is a Liberalism, liberal List of political parties in Japan, political party in Japan. It is the primary centre-left politics, centre-left party in Japan, and as of 2024 is the second largest party in the National Diet behind the ruling L ...

(CDP), allowing members to leave the SDP and join the latter party. The majority of the party supported the agreement and joined the CDP; however, party leader Fukushima herself was opposed to the merger agreement and remains a member of the Social Democratic Party. In the

2021 Japanese general election General elections were held in Japan on 31 October 2021, as required by the Constitution of Japan, constitution. Voting took place in all List of districts of the House of Representatives of Japan, constituencies in order to elect List of member ...

, the party lost one of their two seats.

Policies

Party policies include: * Defend

Article 9 of the Constitution of Japan is a clause in the Constitution of Japan outlawing war as a means to settle international disputes involving the state. The Constitution was drafted following the surrender of Japan in World War II. It came into effect on 3 May 1947 during the oc ...

and declare cities defenseless so that they will not resist in the event of invasion. * Advocate a significant increase in the scope of

social welfare Welfare spending is a type of government support intended to ensure that members of a society can meet basic human needs such as food and shelter. Social security may either be synonymous with welfare, or refer specifically to social insurance p ...

such as

healthcare Health care, or healthcare, is the improvement or maintenance of health via the preventive healthcare, prevention, diagnosis, therapy, treatment, wikt:amelioration, amelioration or cure of disease, illness, injury, and other disability, physic ...

pensions A pension (; ) is a fund into which amounts are paid regularly during an individual's working career, and from which periodic payments are made to support the person's retirement from work. A pension may be either a "defined benefit plan", wher ...

social security Welfare spending is a type of government support intended to ensure that members of a society can meet basic human needs such as food and shelter. Social security may either be synonymous with welfare, or refer specifically to social insurance ...

and

disability Disability is the experience of any condition that makes it more difficult for a person to do certain activities or have equitable access within a given society. Disabilities may be Cognitive disability, cognitive, Developmental disability, d ...

care. * Opposition to

neoliberalism Neoliberalism is a political and economic ideology that advocates for free-market capitalism, which became dominant in policy-making from the late 20th century onward. The term has multiple, competing definitions, and is most often used pe ...

and

neoconservatism Neoconservatism (colloquially neocon) is a political movement which began in the United States during the 1960s among liberal hawks who became disenchanted with the increasingly pacifist Democratic Party along with the growing New Left and ...

. * Complete disarmament of Japan in accordance with

pacifist Pacifism is the opposition to war or violence. The word ''pacifism'' was coined by the French peace campaigner Émile Arnaud and adopted by other peace activists at the tenth Universal Peace Congress in Glasgow in 1901. A related term is ''a ...

principles. The Japanese Self-Defense Force will be replaced with a force dedicated to disaster relief and foreign aid. * Cancellation of the United States–Japan military alliance, dismantling of United States bases in Japan and replacing it with a Treaty of Friendship. * Introduction of an environmental

carbon tax A carbon tax is a tax levied on the carbon emissions from producing goods and services. Carbon taxes are intended to make visible the hidden Social cost of carbon, social costs of carbon emissions. They are designed to reduce greenhouse gas emis ...

. * Significant increase in the scope of wildlife protection legislation, increasing the number of

protected species An endangered species is a species that is very likely to become extinct in the near future, either worldwide or in a particular political jurisdiction. Endangered species may be at risk due to factors such as habitat loss, poaching, invasiv ...

and setting up of protection zones. * Transition from a mass-production/mass-consumption society to a sustainable society in coexistence with nature. * Clampdown on harmful chemicals, e.g. restriction on use of agricultural chemicals, ban on

asbestos Asbestos ( ) is a group of naturally occurring, Toxicity, toxic, carcinogenic and fibrous silicate minerals. There are six types, all of which are composed of long and thin fibrous Crystal habit, crystals, each fibre (particulate with length su ...

, tackling

dioxin Dioxin may refer to a number of different substances. Most notably: * 1,2-Dioxin or 1,4-dioxin, two unsaturated heterocyclic 6-membered rings in which two carbon atoms have been replaced by oxygen atoms, which gives the molecular formula C4H4O2 ...

and soil pollutants. * Increased investment in public transport, encouraging a switch from road to rail and from petrol powered buses to hybrids, electric vehicles and

light rail transit Light rail (or light rail transit, abbreviated to LRT) is a form of passenger urban rail transit that uses rolling stock derived from tram technology National Conference of the Transportation Research Board while also having some features from ...

. * Opposition to

nuclear power Nuclear power is the use of nuclear reactions to produce electricity. Nuclear power can be obtained from nuclear fission, nuclear decay and nuclear fusion reactions. Presently, the vast majority of electricity from nuclear power is produced by ...

and proposal of a gradual switch to

wind energy Wind power is the use of wind energy to generate useful work. Historically, wind power was used by sails, windmills and windpumps, but today it is mostly used to generate electricity. This article deals only with wind power for electricity ...

as the nation's base energy source. * Abolition of the

death penalty Capital punishment, also known as the death penalty and formerly called judicial homicide, is the state-sanctioned killing of a person as punishment for actual or supposed misconduct. The sentence ordering that an offender be punished in s ...

. * Opposition to

water privatization Water privatization is short for private sector participations in the provision of Water supply, water services and sanitation. Water privatization has a variable history in which its popularity and favorability has fluctuated in the market an ...

. * Supports

feminist Feminism is a range of socio-political movements and ideology, ideologies that aim to define and establish the political, economic, personal, and social gender equality, equality of the sexes. Feminism holds the position that modern soci ...

politics. * Legalization of

same-sex marriage Same-sex marriage, also known as gay marriage, is the marriage of two people of the same legal Legal sex and gender, sex. marriage between same-sex couples is legally performed and recognized in 38 countries, with a total population of 1.5 ...

.Inada, Miho; Dvorak, Phred
"Same-Sex Marriage in Japan: A Long Way Away?"
. ''The Wall Street Journal''. September 20, 2013. Retrieved March 31, 2014.

Leaders

Election results

House of Representatives

House of Councillors

Current Diet members

House of Representatives

* Kunio Arakaki ( Okinawa-2nd)

House of Councillors

Up for re-election in 2025 * Yūko Ōtsubaki ( National PR) Up for re-election in 2028 *

( National PR)

Notes

References

External links

Official website
{{authority control 1996 establishments in Japan Centre-left parties in Asia Democratic socialist parties in Asia Environmentalism in Japan Feminist parties in Asia Full member parties of the Socialist International Left-wing parties in Japan LGBTQ political advocacy groups in Japan Pacifism in Japan Pacifist parties Political parties established in 1996 Progressive parties in Japan Social democracy in Asia Social democratic parties in Japan

History

Before 2000

2000s–2010s

Since 2020

Policies

Leaders

Election results

House of Representatives

House of Councillors

Current Diet members

House of Representatives

House of Councillors

See also

Notes

References

External links