The proletarian parties were a group of political parties in Japan. Several proletarian parties were launched after enactment of the Universal Manhood Suffrage Act in 1925. The Farmer-Labour Party had been founded in December 1925, but banned after only two hours of existence. Three major proletarian parties emerged during 1926, all closely linked to trade union movements and the divisions between the trade unions were largely replicated in divisions between the political parties. The pro-communist trade union centreHyōgikai backed the Labour-Farmer Party. The centrist Japan Labour Union League backed the Japan Labour-Farmer Party. The moderate Sodomei trade union centre backed the Social Democratic Party. All these three parties were constructed on the notion of a worker–peasant class alliance. Another proletarian party in the fray, the Japan Farmers Party differentiated themselves from this pattern by declaring themselves as a party 'by farmers, for farmers'. There were also some local proletarian parties. In 1927, all three major proletarian political founded separate women's organizations. The Kanto Women's League, linked to the Labour-Farmer Party, was however disbanded after a few months on orders from the party leadership. The proletarian parties took part in the 1927 prefectural assembly elections, and their participation was closely watched. Together they had launched 216 candidates, out of whom 28 were elected. The Labour-Farmer Party garnered most of its vote from rural areas, whilst the Social Democratic Party and the regional proletarian parties got most of their votes from urban areas. The Labour-Farmer Party won 13 seats, the Japan Farmers Party four seats, the Social Democratic Party three seats, the Japan Labour-Farmers Party three seats and different local proletarian parties five seats. In the 1928 national Diet election, roughly half of the urban votes for proletarian parties went to the Social Democratic Party whilst roughly half of the rural votes for the proletarian parties went to the Labour-Farmer Party. The proletarian parties managed to win eight seats in the Diet. Overall, the election result was disappointing for the proletarian parties. Many of their prominent leaders failed to get elected. There are different possible explanations to the limited success of proletarian parties in 1928. They lacked the lavish electoral campaign budgets of the established parties. Nor were their leaders, with a few notable exceptions, very well known. Moreover, socialist ideas and movements were treated with a great deal of suspicion by many Japanese voters, limited the appeal of the proletarian parties. Furthermore, the electoral campaigns of the proletarian parties suffered from direct sabotage by state authorities. Police wound disperse electoral meetings, or arrest campaign workers arbitrarily. Considering the fact that each constituency elected 3 to 5 parliamentarians, the fierce competition between the different proletarian parties often resulted in none of them getting elected. Noticing the lack of coordination as an inherent weakness of the proletarian parties, the Social Democratic Party took the initiative to form a joint parliamentary committee. In July 1928, the Proletarian Masses Party was formed, by one former Labour-Farmer Party faction. In December 1928 the Japan Labour-Farmer Party, the Proletarian Masses Party, the Japan Farmers Party and four regional political parties merged, forming the Japan Masses Party. The Labour-Farmer Masses Party was founded in January 1929 by Mizutani Chozaburo, a former associate of the Labour-Farmer Party leaderOyama Ikuo. Mizutani criticized Oyama Ikuo for being too open towards a merger with the centrist sectors of the socialist movement. The Labour-Farmer Masses Party was largely confined to Kyoto. The party was one of the founders of the United Proletarian Party Front in 1929. The party then merged with the Tokyo Proletarian Party, forming the National Conference for a United Proletarian Party which in turn merged with other parties on July 20, 1930, founding the Zenkoku Taishūtō. In November 1929, Oyama Ikuo and his followers founded the New Labour-Farmer Party. The 1930 Diet election was a further set-back for the proletarian parties, only winning five seats; two from the Japan Masses Party, two from the Social Democratic Party and Oyama Ikuo from the New Labour-Farmer Party. The proletarian parties mostly condemned the 1931 Mukden Incident and the resulting Japanese invasion. However, they did so in varying degrees. The Social Democratic Party was more candid in its condemnations of the Incident. Notably, the main backer of the Social Democratic Party, Sodomei, did not oppose the Incident. The Social Democratic Party merged with the National Labour-Farmer Masses Party in July 1932, forming the Shakai Taishūtō.
