The was a short-lived political party in the pre-war Empire of Japan.
The Kenseikai was founded on 10 October 1916, as a merger of the Rikken Dà Âshikai (led by Katà  Takaaki), Chà «seikai (led by Ozaki Yukio) and the Kà Âyà « Club (a minor opposition group). Led by Katà  Takaaki, the new party was united by its opposition to the policies of the ruling Rikken Seiyà «kai under Prime Minister à Âkuma Shigenobu. The party was supported financially by the Mitsubishi zaibatsu, due to family ties with Katà  Takaaki. Party leaders included Hamaguchi Osachi and Adachi Kenzà Â. The merger gave the Kenseikai a total of 198 seats in the Lower House of the Diet of Japan, thus forming a majority, and raised the expectation that Katà  Takaaki would become the next prime minister.
However, the position of prime minister was a direct appointment from the Emperor per advice provided by the genrà Â, and in this case, the genrà  unexpectedly nominated General Terauchi Masatake instead. In protest, the Kenseikai initiated a no confidence motion, which subsequently dissolved the Diet and led to the political isolation of the Kenseikai for almost a decade. During its period in the opposition, the Kenseikai strongly opposed the Siberian Intervention and pushed for greater rights for labor unions.
In the 1924 General Election, the Kenseikai secured 150 seats, making it the largest single party in the Lower House, but without a majority. Katà  agreed to form a coalition government with the Rikken Seiyukai (led by Takahashi Korekiyo), which had 100 seats, and the Kakushin Club (led by Inukai Tsuyoshi), which had 30 seats. This three-party coalition (Goken Sampa Naikaku) was the first ruling coalition government in Japanese history, and used its majority to focus on domestic political reform and a moderate foreign policy.
It pushed strongly for rule under the Meiji Constitution, without influence or control by the genrà Â. It also favored universal male suffrage (which led to the General Election Law) and much needed reforms in labor laws and in the economic situation for farmers. However, despite its liberal image, the coalition passed the Peace Preservation Law in 1925.
Following Katà Â's death, the party was led by Wakatsuki Reijirà Â, but his cabinet was unable to weather the Shà Âwa financial crisis of 1927. The Kenseikai merged with the Seiyà « Hontà  in June 1927 to form the Rikken Minseità Â.