Masakazu Sekiguchi Hiroyuki Nagahama Yukihiko Imasaki Kazuo Ueda
The party was established on 16 November 1945 by a group of 273 MPs, of whom 89 had been Rikken Minseitō members and 46 from Rikken Seiyūkai; many had been elected with the backing of the Imperial Rule Assistance Association in the 1942 general elections.
[7] Machida Chūji was appointed party president after the post was turned down by Keizo Shibusawa.
[7] Due to it high proportion of members involved in wartime politics, it was the most affected party in the post-war purge, with 238 MPs and all but one its central committee members barred from politics.
[7] At the end of March the decision was taken to dissolved the JPP and form the Democratic Party.