Since the wide corpus of Chan 禪 literature includes a significant number and a consistent variety of ironic features such as puns, wordplay, extravagant acts, and so forth, a clarification of the role and functions of irony is especially relevant to this framework. The idea of the present essay is that irony works in Chan Buddhism as a functional strategy purposely employed in textual compositions and oral communication. Analysing the Blue Cliff Record (Biyan Lu 碧巖錄), one of the most influential and significant texts in the history of East Asian Buddhism, I individuated three functions of irony that clarify its role in the wider context of Chan rhetoric. Specifically, these functions consist in performing a rhetoric of self-desecration, inducing amusement, and instilling doubt. Upon defining the notion of irony, the current essay expounds on these functions with reference to the text, then the role of irony in the Blue Cliff Record is finally identified as a hermeneutic device.