The present study aims to analyze the rhetorical structures of intercultural business email communication between non-native writers; Thai and Japanese. 305 pairs of business inquiry and reply emails collected from three Thailand-based companies which engaged in an email interaction with Japanese partners. They were analyzed using intercultural rhetoric analysis based on the framework of move analysis. The results revealed that there was a distinctive difference between both groups of writers in composing emails. In an inquiry email, it was found that M1, M2, M4, M5, and M7 constitute the main email structure of Thai writers, but the moves such as M1, M4, and M7 are considered the core components for Japanese writers. For reply emails, all six moves are considered essential moves for Thai, but three moves such as M1, M3, and M6 are the core components of Japanese writers. The results also indicated that both Thai and Japanese writers composed diverse patterns of business emails; however, the majority of Thai writers composed business inquiry and reply emails using six move patterns whereas the four move patterns were used by the majority of Japanese writers.