This paper analyses the central puzzle of why the Five-Year Plan based National Development Planning, adopted by both China and India in the mid-twentieth century, has been powerfully reinforced in the former while being formally abandoned in the latter. It attempts to answer two questions: what have been the adaptation patterns of FYP-based planning in each nation, and how can their divergent pathways be explained? The analysis employs a conceptual framework focusing on coordination capacity for collective action and learning capacity for adaptability. It identifies distinct adaptation patterns: inertia/routine, disruptive, conducive, and systematic. The paper finds this divergence stems from China’s ability to institutionalize high coordination and learning capacities for systematic adaptation, whereas India faced complex challenges to build robust coordination capacity ultimately rendering the instrument obsolete. The paper argues that adaptive change in FYPs is contingent upon responses to external and internal crises, leadership dynamics, and governing traditions.