ABSTRACT
This paper investigates how the historical and geopolitical relationship between China and Japan has shaped collective psychology. Using language-based methods across three domains—public sentiment, political discourse, and academic literature—we conducted three complementary analyses. First, word embedding techniques applied to two large-scale Chinese text corpora show that sentiment toward Japan improved from the 1950s to 1980s before declining, a pattern that parallels Japanese sentiment toward China. Second, topic modelling of Japanese parliamentary records reveals that discussions of China over the past eight decades have been embedded in shifting global and regional geopolitical concerns, with recurring attention to war memory and maritime disputes. Third, a review of English-language psychology literature indicates that early studies (1940s–1980s) focused on war and stereotypes; after the 1990s, research emphasized historical memory and reconciliation, and more recently, topics such as Chinese students in Japan, cross-border mobility, and business relations—mirroring growing socioeconomic interdependence. Together, these analyses provide a multilayered view of how sentiment, identity, and historical memory co-evolve with the geopolitical landscape in Sino-Japanese relations.