  It is common sense in Mahāyāna Buddhism that all living beings have Buddha-nature. So, why is the monk asking what is an obvious and absurd question, and why is Zhaozhou giving a paradoxical answer? In discussing this hwadu and instructing his students how to work with it, Chinul suggests that Mu is “the weapon which destroys wrong knowledge and wrong understanding”. Zhaozhou’s “Mu” here does not mean an affirmative answer nor a negative one. The student of Sŏn here then should not consider it in relation to a doctrinal theory—one only needs to “be concerned about keeping this question before [one] and [one’s] attention always focused”. In this way, when the student of Sŏn follows the tortuous yet fruitful path of hwadu patiently,   