Turnout: 53.68%
About this election
Japan held a snap general election for the 465-seat House of Representatives on 22 October 2017. Prime Minister Shinzō Abe's Liberal Democratic Party (LDP) won 284 seats and, with its junior coalition partner Komeito (29 seats), retained a two-thirds supermajority of the lower house. The newly founded, social-liberal Constitutional Democratic Party (CDP) emerged as the largest opposition force with 55 seats, overtaking the centre-right Party of Hope (Kibō no Tō, 50), which had been launched only weeks earlier by Tokyo governor Yuriko Koike. The Japanese Communist Party took 12 seats, Nippon Ishin no Kai 11 and the Social Democrats 2, with 22 independents. Turnout was 53.68%, the second-lowest in the postwar era.
Japan is a constitutional monarchy and parliamentary democracy whose bicameral National Diet comprises the House of Representatives (lower house) and the House of Councillors (upper house). The Emperor is a ceremonial head of state with no political powers; sovereignty rests with the people under the 1947 constitution. The lower house is the more powerful chamber: it designates the prime minister, and it can override the upper house's rejection of a bill by a two-thirds majority and prevails outright on the budget and the ratification of treaties. Members serve four-year terms unless the house is dissolved earlier, which in practice it almost always is — no postwar lower house has run its full term in recent decades.
The House of Representatives is elected by a parallel mixed-member system introduced in 1994 to replace the old multi-member districts. Of the 465 members, 289 are returned from single-member districts by first-past-the-post and 176 by closed-list proportional representation in 11 regional blocs. Voters cast two ballots, one for a constituency candidate and one for a party list. Because the two tiers are counted separately, with no compensation between them, the system is majoritarian in effect and tends to reward the largest party. Candidates may stand simultaneously in a district and on their party's list; a district loser can be "revived" from the list, and parties often rank such dual candidates equally and let the closeness of their district defeat (the sekihairitsu) decide the order. The prefecture map on this page colours each prefecture by the party that won the most of its single-member districts.
Abe, who had returned to power in December 2012, called the election a full year early, citing the need for a fresh mandate to handle the North Korean missile and nuclear crisis and to redirect revenue from a planned 2019 consumption-tax rise toward childcare and education. Critics saw opportunism: the main opposition was in disarray, Abe's approval had recovered over the summer, and the LDP wanted to capitalise before scandals over alleged cronyism — the Moritomo Gakuen land sale and the Kake Gakuen veterinary-school affairs — could regroup the opposition against it.
The campaign was defined by the implosion and rebirth of the opposition. The Democratic Party, the largest opposition force, effectively dissolved itself into Koike's new Party of Hope. But Koike's refusal to accept liberal and left-leaning members — she spoke of "excluding" them from her conservative, pro-revision project — prompted Yukio Edano to found the Constitutional Democratic Party within days. The CDP's unapologetically liberal, anti-constitutional-revision stance struck a chord, and it outpolled the Party of Hope, whose momentum evaporated once Koike declined to stand for a Diet seat herself and remained in Tokyo.
The dominant force was the LDP, the broad centre-right party that has governed Japan for almost all of the period since its founding in 1955, allied since 1999 with the Buddhist-backed centrist Komeito. Opposing them were the new liberal CDP (Yukio Edano), the conservative-reformist Party of Hope (Yuriko Koike), the Osaka-based populist Nippon Ishin no Kai, the long-established Japanese Communist Party and the small Social Democratic Party, heir to the once-mighty Japan Socialist Party.
Abe ran on national security amid North Korean provocations and on the continuity of "Abenomics", his programme of aggressive monetary easing, flexible fiscal policy and structural reform. The fractured opposition could not present a single alternative prime minister, and the late, chaotic birth of two new parties left voters with a confused choice. A powerful typhoon on polling day further depressed turnout.
The supermajority left Abe well placed to pursue his long-standing goal of revising Article 9 of the pacifist constitution, though that ambition would ultimately stall for want of agreement among the pro-revision parties and public caution. The result extended what became the longest premiership in Japanese history; Abe would go on to win the LDP presidency again in 2018. In the constituency tier the LDP led 45 of the 47 prefectures, its dominance interrupted only in scattered urban and Tōhoku districts where the CDP and independents prevailed.
In the December 2014 snap election Abe's coalition had also won a two-thirds majority on a record-low turnout, so 2017 essentially renewed a commanding position rather than creating one. The persistence of LDP dominance across both votes underlined how a divided and frequently re-founded opposition struggled to convert discontent into seats.
Turnout of 53.68% was depressed in part by Typhoon Lan, which struck on election day, although heavy early voting cushioned the impact. Persistently low participation has been a feature of recent Japanese elections, reflecting weak opposition competitiveness, the absence of credible alternation in power and a degree of voter fatigue.
Ministry of Internal Affairs and Communications (Sōmushō) and NHK — soumu.go.jp.
Compiled and reviewed by Bartłomiej Paruzel, Election Data Analyst, from official results. See our data methodology.