He was noted for his support of the newly established People's Republic of China (PRC) as well as the criticism of United States–Japanese relations, making him a polarizing figure.

Asanuma was assassinated with a wakizashi, a traditional short sword,[1] by far-right ultranationalist Otoya Yamaguchi while speaking in a televised political debate in Tokyo.

His violent death was seen in graphic detail on national television by millions of Japanese, causing widespread public shock and outrage.

In 1936, Asanuma was elected to the National Diet of Japan for the first time, as a member of the newly-formed Social Masses Party, which merged into the Imperial Rule Assistance Association in 1940.

[11] He lived modestly in public housing his entire life, and was particularly popular among ordinary laborers, small shopkeepers, and other members of the working class.

[12] However, historian Andrew Gordon argues that Asanuma was consistent in his antipathy to western imperialism and a desire for Asia to chart its own course in world affairs.

[12] On 12 October 1960, Asanuma was assassinated by 17-year-old Otoya Yamaguchi, a right-wing ultranationalist, during a televised political debate ahead of upcoming elections for the House of Representatives.

Japanese public broadcaster NHK was videorecording the debate for later transmission and the tape of Asanuma's assassination was shown many times to millions of viewers.

Shortly after his death, conservative prime minister and erstwhile electoral rival Hayato Ikeda captured the mood of his fellow lawmakers when he gave a heartfelt eulogy for Asanuma on the floor of the Diet.

Commemorating Asanuma as a "speech-giving everyman" (enzetsu hyakushō), Ikeda declared: You made service to the people the core of your political principles.