Joshu's Mu

Joshu  was a famous Chinese Zen Master who lived in Joshu, the province from which he took his name. One day a troubled monk approached him, intending to ask the Master for guidance. A dog walked by. The monk asked Joshu, Has that dog a Buddha nature or not? The monk had barely completed his question when Joshu shouted: “MU!

Of all koans, Joshu’s Mu is the most famous. It is extremely popular with Zen Masters, who frequently assign it to novices. If the student tends properly to business, Mu comes to resemble a hot iron ball stuck in his throat—he can neither swallow it nor spit it out. The importance of Joshu’s Mu is its succinct (one syllable) revelation of Buddhism. Mu is the negative symbol n Chinese meaning “not” or “no-thing.” 

Mu is also a basic concept in Oriental philosophy. There is a relative Mu and an Absolute Mu. The relative Mu, in Chinese characters, is the opposite of U which means “is.” The Absolute Mu of Zen Buddhism transcends “is” and “is not.” In order to “understand” this koan, it is necessary to be aware of this distinction. When the monk asked Joshu, “Has that dog a Buddha-nature or not?” he was asking not only from the standpoint of his own troubled mind, but from the basic Buddhist teaching that “all beings have Buddha nature.” Joshu realized this.

His “MU!” was a blow aimed at breaking, or untying, the monk’s attachment to that teaching. The essence of Buddha’s teaching is non-attachment. All human troubles and sufferings, without exception, are due to attachment. Even attachment to the idea of nonattachment is attachment! Joshu wanted the monk to transcend the relative world, transcend the teachings, transcend U and Mu, transcend Buddhism, and gain the free and independent world of enlightenment.

Satori, or enlightenment, is this new dimension or perspective in life. Ordinary human life is always attached to the relative: the “is” and the “is not, good and bad, right and wrong. But life itself is constantly changing; the condition of society changes; right and wrong changes; every situation is different according to time and place. Static concepts are not appropriate to life. Thus, Mu is crucial: it offers no surface upon which the intellect can fasten. The word Mu must be experienced as the world of “MU”