In perhaps the most famous koan of all time, a monk asks Chao-chou, a Chinese Chan master, “Does a dog have buddha nature or not?” Joshu’s reply, “Mu,” is not so easy to translate. It’s most often a prefix showing the absence of something, but it’s also the “emptiness” heard over and over in the Heart Sutra. Either way, it’s most definitely not “Yes!”

The real meaning of this mu has had Zen students spinning for centuries. 

A commentary by Wumen, a dharma descendant of Chao-chou, ends with this verse:

Has a dog buddha nature? This is the most serious question of all. If you say yes or no
you lose your own buddha nature.

Depending on who you ask, buddha nature is either a kind of seed of buddhahood, or a cause of it, or maybe it’s the foundation on which it all rests. Dogen, the founder of Soto Zen in Japan, wrote at length about how buddha nature is, ultimately, just everything—it’s a synonym for reality itself. Through that lens, it either means a lot or, well, nothing at all (but most teachers veer toward “a lot”).

For Tibetan teacher Yongey Mingyur Rinpoche, buddha nature is the central message of Buddhism. In his teaching he writes, “The message that I think Buddhism has to offer the world in this troubled century is the Buddha’s insight that we all have buddha nature.” He tells us that our hearts “are naturally open and compassionate.” Although “this buddha nature is always with us,” coming to see that truth is what makes all the difference: 

“Recognizing these qualities is like discovering a treasure that’s been buried right beneath our feet. What we discover might feel new and fresh, but it’s our discovery that is new, not the qualities themselves. This discovery of our own buddha nature is the solution to the problems we face. It gives us the confidence, the compassion, and the wisdom to deal with our own challenges and the suffering of the world with an open heart and a clear mind.”

Wumen worked on the koan of the dog and buddha nature for six years before breaking through. He later offered this advice: 

“Make your whole body a mass of doubt, and with your 360 bones and joints and your 84,000 hair follicles, concentrate on this one-word mu. Day and night, keep digging into it. Don’t consider it to be nothingness. Don’t think in terms of ‘has’ or ‘has not.’ It is like swallowing a red-hot iron ball. You try to vomit it out, but you cannot.”

More than a thousand years after Chao-chou, Shunryu Suzuki Roshi, in a dharma talk at San Francisco Zen Center, said: 

“Everyone knows that buddha nature is everywhere and includes everything. But if we all are buddha—if buddha nature is everywhere—why practice zazen?

“Consider the air: it too is everywhere, but until we use a fan, we are not aware of it. Zazen may be likened to the fanning. However, awareness of buddha nature, or the solution to mu, are not our only problems. So, there is no need to be narrowly overconcerned with what buddha nature refers to.”

Whether it’s a red-hot ball or a kind of background hum, the question is there, and it’s the kind that brings practice alive. How would you define buddha nature? Is it the start of something, or is it the whole thing? Can you see it in others, or in yourself? If your answer is yes, what does that look like to you? And to circle back to the dog: is there any place, any being, where buddha nature is absent?

Your answers reveal what you think this practice is, why you would take it up, and what you believe you’re capable of. They reveal your understanding of reality itself. Right now, in this moment, is anything missing? It’s a question that’s as big as they come. There’s a reason why people can’t stop talking about that dog.

The Emily Dahl Foundation