In this Quantitative History Lecture, Debin Ma of the University of Oxford will present his paper which revisits the old thesis of the contrasting paths of modernization between Japan and China. It develops a new analytical framework regarding the role of ideology and ideological change—Meiji Japan’s decisive turn towards the West pitted against Qing China’s lethargic response to Western imperialism – as the key driver behind this contrast. They show that the structural difference between Tokugawa Japan’s feudal, decentralized political regime and Qing China’s centralized bureaucratic system generated differential benefits and costs for regime change and ideological realignment in mid-19^th century. Debin Ma and his team build a historical narrative to trace the origin of this political bifurcation to the Medieval period. Their new analytical framework supported by a historical narrative and empirical evidence highlights the crucial role of regime change during late 19^th century China and Japan through the lens of ideological change as distinctive but complementary elements of culture and institutions.