In 1970, Japan hosted the world exposition under the theme of "Progress and Harmony for Mankind," Along with the 1964 Tokyo Olympics, the Japan World Exposition of 1970 (Expo``70) provided Japan with the opportunity to showcase its postwar economic growth and technological optimism for both domestic and overseas audiences. With the help of technological and artistic experiments, leading Japanese artists and intellectuals actively participated in this event`s production, Among the participants, the experimental architects of the Metabolist group played a crucial role in the creation of a futuristic virtual city at Expo``70. Ostensibly, the image of the future promoted at Expo``70 was a fantastic techno-utopia. However, this vibrant utopian vision of the future, based on technological optimism is suspicious, given that a mere twenty-five years had passed since Japan`s defeat in WWII. The Metabolists` involvement in Expo``70 fuels this suspicion in; their earlier work suggested different strategies of imagining the future based on an alternative means to deal with the traumatic past. The apocalyptic sentiment of the Metabolism, which resulted in no small part from their struggling with the destructive war and ruined cities, went against Expo`s official rhetoric of techno-utopia which was founded on suppression, rather than acceptance, of the tragic past. This is a particularly intriguing aspect of the young architects` participation in the fair. Did the Metabolists sympathize with or criticize the Expo`s utopian promise? If the Metabolists` attitude toward the future and technology was contrary to Expo`s optimistic future, why did the Metabolists participate in this national event and what role did they play? How might the Metabolists` engagement in Expo``70 be evaluated? With these questions in mind, this study addresses the Metabolists` engagement in Expo``70, focusing on the multi-layered, compatible yet contradictory visions of the future, This study not only explores in detail Metabolists` architectural con-cept about the future and technology but also revises the seamless narrative of Expo`s rosy future. Ultimately, I hope to illuminate how postwar Japanese society imagined its future in response to the traumatic past and contradictory present.