International Relations theory about East Asia has increasingly argued that East Asia before Western penetration enjoyed a protracted peace. As explanations, a Chinese military hegemony would fit realist theory fairly well, while a cultural peace based on shared Confucian norms would be a significant anomaly. A Confucian Long Peace challenges widely held, albeit Eurocentric, realist presumptions including the perils of anarchy, the arms-racing and misperception of the security dilemma, and the regularity of power balancing. This article therefore investigates, first, whether such a peace did in fact exist, and, second, whether this might be attributed to Confucianism. A cultural peace theory requires a strong anti-war cultural norm and a shared sense of community. Skepticism is established by examining three comparative cultural spaces that nonetheless did not enjoy a culturally informed peace: the classical Greek citystate system, early modern Christendom, and the contemporary Arab state system. All were deeply riven and competitive. Nevertheless, empirical investigation of the last Chinese (Qing) dynasty before the Western arrival (1644-1839) demonstrates that it was remarkably peaceful toward its Confucian neighbors, while more 'normally' exploiting its power asymmetry against non-Confucian ones. Processtracing specialized Chinese practices toward fellow Confucians suggests that the low Confucian war finding emanates from cultural restraint.