Rikken Seiyūkai

Rikken Seiyūkai
立憲政友会
LeaderItō Hirobumi
Saionji Kinmochi
Hara Takashi
Takahashi Korekiyo
Tanaka Giichi
Inukai Tsuyoshi
Suzuki Kisaburō
FounderItō Hirobumi
FoundedSeptember 15, 1900 (1900-09-15)
DissolvedJuly 30, 1940 (1940-07-30)
Merger ofKenseitō
Teikokutō (factions)
Kakushin Club (factions, 1925)
Merged intoImperial Rule Assistance Association
Succeeded bySeiyūhontō (Mainstream faction, 1924, via Shinsei Club)
Shōwakai (pro-Tokonami faction, 1935)
HeadquartersTokyo City
NewspaperSeiyūkai
Chuo Shimbun (ja)
IdeologyConservatism (Japanese)
Liberal conservatism
Modified capitalism
Monarchism
Anti-particracy
Faction:
Gradualist economics
Keynesianism
Political positionCentre-right to right-wing

The Rikken Seiyūkai (立憲政友会; Association of Friends of Constitutional Government) was one of the main political parties in the pre-war Empire of Japan. It was also known simply as the Seiyūkai.

The party was founded in 1900 by Itō Hirobumi as a pro-government alliance of bureaucrats and former members of the Kenseitō. It came to power in the same year when Itō became the Prime Minister. It was the most powerful political party in the House of Representatives from 1900 to 1921. After the assassination of party leader and Prime Minister Hara Takashi in 1921, a large part of the party defected to form the Seiyūhontō in the 1924 general election, leading the party to lose a significant amount of seats. It regained a very slight plurality of 217 seats in the 1928 general election, resulting in a hung parliament.

The party was reduced to 174 seats in the 1930 general election, which led to the formation of a Constitutional Democratic Party-led government. It won the 1932 general election with 310 seats, leading its leader Inukai Tsuyoshi to become Prime Minister; Inukai was later assassinated in the May 15 incident in 1932. The party was again reduced to 174 seats in the 1936 general election, later winning 175 seats in the 1937 general election. In 1940, the party voted to merge itself to the Imperial Rule Assistance Association, which became the sole ruling party of Japan until 1945.