This chapter traces the evolution of orthodox and heterodox thought in Chinese intellectual history, examining how the concept of heterodoxy developed from early Confucian critiques to systematic doctrinal frameworks. It analyzes various interpretations of heterodoxy, from “strange abilities” to “different views,” and explores how Confucian scholars from Mencius through the Song dynasty approached the challenge of heterodox teachings. The chapter examines the establishment of the “lineage of the Way” as a framework for maintaining orthodox transmission, beginning with the heritage of sage wisdom and continuing through figures like Han Yu and the Neo-Confucian movement. It concludes by analyzing how the rise of Neo-Confucianism led to factional politics and the eventual prohibition of factionalism, demonstrating the political implications of philosophical orthodoxy.