The standardization of the Chan school Pure Regulations texts and of the rituals described within them is emblematic of the standardization of both the institutional structure of Chan monasteries and their rituals. It is also emblematic of the direct intervention by the state in the ritual practice of Chan Buddhism. From this example with the Chan tradition, we can see that although the standardization of rituals was encouraged by the state, the state could not easily create new rituals. Instead, rituals had to follow traditions that had been established centuries previously. Nonetheless, celebration of the emperor's birthday, as well as rites for rain, rites against floods, droughts, epidemics and other natural disasters have been appended to Chan's ancient traditions, as products of cooperation between religion and politics. By comparing several Pure Regulations texts compiled in the Yuan dynasty with those of the Song dynasty, the present article provides an account of the history of the standardization of Chan rituals and describes some of the specific ritual procedures. In addition, it uses ritual announcements and ritual prefaces written by Yuan dynasty Chan monks to describe minor differences found in the structures of the standardized rituals and to ascertain how the rituals were actually practiced. From this, this article hopes to reconsider the importance of the Yuan dynasty in Chan history and reevaluate the influence of the standardization of Chan rituals upon developments occurring over the centuries that followed.