His support of the Chinese Communist Party was criticized both from the right and by his colleagues.
Asanuma was assassinated by 17-year-old Otoya Yamaguchi, an extreme rightist, at a televised rally for the coming Lower-house election. Yamaguchi rushed and fatally stabbed Asanuma, and was subdued moments later.
The entire incident was captured on camera.
The assassin, Otoya Yamaguchi, committed suicide a few weeks later.