Chan (Jp. Zen) Buddhism, which came to prominence as a thriving monastic institution in China and Japan during the twelfth and thirteenth centuries, is often thought to be antithetical to and strongly criticized by Confucianism, especially by the leading philosopher of the period Zhu Xi, for emphasizing quietist methods renouncing everyday life as well as unconventional behavior with antinomian implications that undermine societal harmony. These iconoclastic Chan ideals are expressed in paradoxical gong’an (Jp. kōan) stories with poetic and prose commentaries. Zhu Xi disparaged Chan’s pursuit of enlightenment, rather than moral cultivation, and viewed meditation as a withdrawal from ethical concerns that favored emptiness over concrete particularities and hollow words over upstanding social activities. Recent scholarship features debates about whether and to what extent Zhu Xi himself was sympathetic to Chan, a practice he explored in his early career but soon abandoned. As this chapter shows, Chan was greatly influenced by Confucian thought in key aspects of its approach to integrating contemplative self-awareness with clerical fellowship. Elements of moral practice suggested in monastic rules and didactic Chan poetry reflect the standpoint of communal labor indicated by the saying attributed to Tang-dynasty master Baizhang, “A day without working is a day without eating” (一日不做. 一日不食).