The Zen koan is one of the least understood of Japanese creations, by either foreigners or even many Japanese – but that is by design. The essence of a koan is that it is not comprehensible by the rational mind, but instead works subtly, over time, on the subconscious.

The koan – based on the Chinese word gong’an, which is a compound word meaning, literally, “public case” – is an extremely complicated form, one that is deeply embedded in monastic discipline and Buddhist study. It is the result of more than a thousand years of development and discussion and thus is easily misunderstood and even more easily caricatured.

But the koan serves a very specific function within Zen Buddhism. It is meant to test the student, first to create what is called “great doubt,” and then to measure how far he has developed in his understanding. A teacher can see, through the way the student processes a koan, how much progress towards understanding he or she is making. There is, in fact, a whole “curriculum” of more than 100 koan that a student will slowly work through over many years of study.

For the rest of us, some koan may be familiar, and can even come to express a general insight that we’ve gained through even casual study of Zen. Indeed, the most famous koan of our time is very famous indeed, for it asks a question that anyone can understand, yet few can adequately answer:

“What is the sound of one hand clapping?”

Spoiler alert: There is no answer. A koan is not always a question – it can be a short conversation, it can be a declaration or it can be a dialog. But no matter the form, even if it is as simple as the one above, the “answer” is not to answer the question. The “answer” is to keep asking the question.

Perhaps you’re already confused. Perhaps that’s good.


Other koan that have become well known through their appearance in conversations or even media through the years include:

– What was your original face before your mother and father?
– If you meet the Buddha on the road, kill him.
– Look at the flower and the flower also looks.

Koans have been compared to court rulings that are subsequently modified or expanded or redefined by various Zen masters. But they are also most certainly a literary form, based on the wordplay, metaphor and use of allusion of any number of Chinese and Japanese literary forms. Yet there is a practical purpose to the use of a koan, and that purpose is not literary: It is simply to keep one practicing Zen.

The koan works because it is not a thing; it is a dynamic activity, a verb more than a noun, a process. While there may eventually be an answer that comes, or an insight, it may also be that that insight is still not what the koan can teach. Perhaps one will contemplate the koan for years; perhaps its essence will be revealed in an instant.

This is perhaps one of the toughest concepts to understand. But the point is in the attempt: the koan is both the “thing” being sought and the attempt – or the ongoing attempts – to understand.


At the same time, there are correct answers to koans, though how that plays out is a result of the interaction between the student and the master, and may be assessed based on the master’s interaction with the student. It may be that the master’s assessment of the student’s understanding comes through in the way the student handles the koan.

Obviously, despite the fact that many people have heard some of these koan, they are not simply aphorisms to be trotted out to explain a spiritual truth. Any use of them in this manner will fall short of what a koan can do. The only way a koan is likely to “work” is through a long, detailed process of dialog between master and student.

In some traditions, this can take ten years or more, depending on the student. But there is a point at which the successful student is said to have “learned” the koan curriculum. But it is a complicated, lengthy and in some cases, a fairly obscure knowledge. The processes around it are complex and daunting, but a mastery of that process is something to which serious students of Zen aspire.

For the rest of us, the koan may remain a thing of mystery, or perhaps just a momentary diversion, something to play with. It may have value in this manner, but it is also clear that any understanding of it is liable to be ephemeral at best. The koan will continue to elude rational understanding; for that is its purpose.