In this article, we trace the development of Hatano's research, focusing on the core of his research interest, namely, expertise, conceptual development, and classroom learning. He held both Piagetian constructivist views and Vygotskian sociocultural perspectives in balance, and preferred to study human cognition executed in everyday life. This brief review strongly suggests that Hatano consciously or subconsciously introduced Japanese perspectives into the areas of human development and education, which often contributed to the expansion and enrichment of mainstream viewpoints constructed within the context of the Occidental research culture.