The Proletarian Masses Party (無産大衆党, Musan Taishūtō) was a short-lived political party in Japan. It was founded on July 22, 1928 by the Rōnō faction (that had belonged to the Labour-Farmer Party, before that party was banned in April 1928). Suzuki Mosaburō became the general secretary of the party.[1] Yamakawa and Sakai Toshihiko functioned as 'elder' advisors in the party. Other prominent founders of the party were Kuroda, Inamura Junzo and Okada.[2][3]
The Proletarian Masses Party claimed to have around 2,500 members. At the time of its foundation, the party declared its intention to struggle against leftwing sectarianism and rightwing disruptionism.[1] The founders of the party were critical of the leadership of Oyama Ikuo in the remains of the Labour-Farmer Party, claiming that Oyama Ikuo was too hostile to a merger with the centrist Japan Labour-Farmer Party.[4] The party was in fierce competition with the Oyama Ikuo-led group over the loyalty of former Labour-Farmer Party activists and sympathizers.[2]
In October 1928 a women's organization linked to the Proletarian Masses Party, the Proletarian Women's Alliance, was founded.[5]
On December 20, 1928 the party merged with the Japan Labour-Farmer Party, the Japan Farmers Party and four regional political parties, to create the Japan Masses Party.[6][7][8] The women's wing merged with the centrist National Women's League in January 1929, founding the Proletarian Women's League.[9]