Shomei Tomatsu was one of the most infl uential Japanese photographers of the post-war era, and his raw and impressionistic style signaled a break from the quiet formalism that had defined earlier works of photography. Moreover, it is noteworthy that his “group-photographs (gunshashin)” is distinguished from the “photo-realism movement” and “photojournalism”, both of which were dominant in the 1950s. On the other hand, a review of prior research indicates that Tomatsu had been regarded as a new generation artist who emerged in the 1960s, whose art was characterized by visual images. The symbolism of his work had generally been discussed in a limited manner by focusing, almost solely, on the “group-photographs”. In other words, little was known about how he faced and understood the reality of postwar Japan. In the previous study, the authors examined how he deepened his understanding of the lives and deaths of atomic bomb victims in Nagasaki over 30 years. We devised and applied a new methodology that enabled us to grasp the true essence of the photographer’s spiraling thoughts and emotions refl ected in his practical actions. We found that Tomatsu gradually observed individuals in their everyday lives, who lived with the memories of the unforgettable atomic bomb. The above fi nding brings up a question that has remained unanswered: How did he capture the intricacies of social change from the postwar years of recovery to the rapid-growth era, which was strongly characterized by Americanization? Specifi cally, while previous research has emphasized his critical view of the US, it is necessary to focus on the bitter inner struggle he went through due to his fateful encounters with US military bases as an adolescent teetering on the brink of starvation. It was this struggle that drove him to journey into the archipelago, including Nagasaki, for more than half a century. Therefore, the purpose of this study is to describe how he expressed the reality of Americanization in Japan during the 1950s to 60s from the perspective of the new methodology mentioned above. In particular, it is significant to note that his work from those decades suggests that he was constantly infl uenced by his traumatic experience of war. In conclusion, it is clarifi ed that Tomatsu photographed every human life with empathy in the 1950s, which was still emotionally scarred due to the aftermath of the defeat, while the postwar reconstruction was close to an end. Furthermore, in the 1960s, he kept his watchful eyes over the inseparable bonds between Japan and the US, although he had so far expressed antipathy to the never-ending occupation despite the Japanese independence. Most importantly, in his eyes, the true essence of the occupation was not just accepting an American way of life but also integrating the radical changes of the political and economic system, as represented by democracy, into the reborn nation. However, in the 1970s, he painfully realized that Japan, which had become one of the world's top economic powers, gave short shrift to the lives of the common people. From this, it has followed that he looked straight at the unforgettable death and anguish, set against the postwar affluence, based on his own formative experiences