The 1970 Japan World Exposition in Osaka is often understood as a spectacle of Japanese ultramodernity. However, recent research suggests that the Expo instead represented the rise of post-modernism in Japan. Abandoning mass politics, the Expo became a space for postmodernist political irony, such as the Black Sun Face that Okamoto Tarō directed at the Shōwa Emperor during the opening ceremony.This article argues that both creators and protesters of the Expo challenged Western-liberal industrial modernity through the politics of diversity. At the forefront of protests against the Expo were the Protestant Christian students of the United Church of Christ in Japan, who banned the participation of their congregations in the Expo. However, the Expo’s actual planners also subverted the western-liberal industrial modernity at its heart. The Kangaerukai—comprising Kyoto University academics, many from the Institute for Research in Humanities, and the science fiction writer Komatsu Sakyō—envisioned the Expo as a festival that would focus on a “diversity” of civilizations, with the “West” at the periphery and Japan as the communicative center. By cooperating with political elites from right and left, the Kangaerukai was successful in creating a high-industrial cultural marketplace, celebrating a capitalist modernity of global diversity, and laying the groundwork for the idea of productivity through cultural self-actualization.