Wu is the Chinese word which equates to Mu in Japanese or Korean. It means ‘none’, ‘not-being’ or ‘without’.
The Mu koan
In Zen Buddhism Mu is used to imply that the question being asked is wrong. The most studied Mu koan has a monk ask Zhaozhou, the Chinese Zen master, “Has a dog Buddha-nature or not?”. Zhaozhou’s answer to the question was “Wu” (or, in Japanese, Mu).
Early Buddhist academiccs debated whether dogs and other animals had a Buddha-nature or not. By answering “Mu” to the question Zhaozhou not only avoided taking sides in the debate, he also avoided following the wisdom of others without denying them. It could also be interpreated that Zhaozhou’s answer implies that yes and no are both right and wrong.
In Pure Spirit
What do you think? Is Mu ever a valid answer or it is the only valid answer?