The Japanese Communist Party (JCP) was officially established in 1922, in the midst of a global wave of socialist and revolutionary movements. In Japan, the aftermath of World War I led to significant social upheaval, economic hardship, and rising labor protests. The Russian Revolution of 1917 inspired many in Japan to pursue similar ideologies, creating fertile ground for leftist politics. Various socialist factions and labor unions began to unify in their opposition to the ruling oligarchy and capitalists, leading to the creation of the JCP as a formal organization.

Key figures, including Kameyama Sakujiro, Takada Gōdō, and other activists, were central to the establishment of the Party. They sought to create a Marxist-Leninist framework in Japan’s political landscape, advocating for the rights of the working class. The Party was instrumental in organizing strikes and labor movements, pushing for better working conditions and rights at a time when industrialization was rapidly transforming Japanese society. Despite facing heavy governmental repression, the JCP was able to thrive underground and became a significant force in Japanese politics, particularly in the following decades.

Throughout its early years, the JCP faced continuous crackdowns, particularly during Japan's militaristic expansion in the 1930s. However, the groundwork laid during this time allowed the Party to survive the challenges of World War II and re-establish itself in the post-war period, becoming an influential political entity in Japan’s democratic system.