ABSTRACT Under British informal imperial policy, East Asia’s system of concessions and settlements rapidly spread and promoted modernization. Especially in the mid- to late nineteenth century, the formative phase of the concession system, Shanghai, Yokohama and Tianjin embraced modern Western urban planning and architectural ideas by implementing Land Regulations (LR). A comparison of institutions, policies and mutual influences resulting from British colonization in these three cities can reflect the intricate internal and external factors that shape their local modernization, which helps explain the urban development trajectory in East Asia. However, existing studies lack comprehensive comparative analysis, exploration of institutional motives for spatial formation and examination of correlations between urban management patterns. Therefore, this study aims to situate the relation between colonialism and modernization in East Asia through an analysis of promulgation process, content changes and spatial impact of LR, the fundamental law of the concessions. This study shows that LR had an inheritance influenced by Consul Alcock. Characteristics of modern urban planning emerged in management and space. The modernization process was shaped by the development of the British native urban governance system, changes in colonial policy and the different social contexts of China and Japan.