Before the plot ratio: balancing density through ambiguity in 1950s colonial Hong Kong

This research examines density regulation in the 1950s Hong Kong that influenced urban planning and policymaking, highlighting the contentious legal concept of ‘one house’ within the leasehold system under colonial land administrations. Utilising archival research and Coasian theory, we elucidate the extralegal treatment of the ambiguous ‘one house’ concept, intended to minimise transaction costs and balance the benefits and harms of high density. This extralegality spurred new housing designs and rent-seeking by private builders. As densification increased, ambiguity in land lease control and case-by-case considerations increased transaction costs, prompting the adoption of universal density control regulations – the forerunners of the Plot Ratio.