The kōan (Chinese: 公案; Korean: 공안, romanized: kong'an) are groupings of related questions and answers which are a paradox. The kōan may be a story which cannot be understood or explained easily.
The kōan can be a special kind of metaphor with a hidden meaning, such as "the sound of one hand clapping".
Kōans are often quite interpretable by rational methods. For some Kōans, the Zen student is expected to find the correct solution by reasoning. For most Kōans, all rational solutions to the Kōan are considered wrong. The actual meaning of these Kōans, their essential function, is only revealed intuitively, without words. There are various views on the meaning of Kōans within Rinzai Zen: While Daisetz Teitaro Suzuki, for example, invokes a contradictory-seeming Sokuhi logic, Ruth Fuller-Sasaki asserts the "fullness of meaning" of Kōans.
The goal of Kōan practice is the realization of non-duality. The illusion that things are different and that the ego has its own existence separate from the rest is to dissolve in the Kōan practice.
The Zen student is given a specific Kōan appropriate to his maturity (e.g., the Kōan Mu: A monk asked Joshu (Chinese Zhaozhou), "Does a dog have Buddha-nature or not?" Joshu replied, "Mu!"). This Kōan is to be presented by the person thus questioned to the master in personal conversation (dokusan) to show that he has grasped the true content of the Kōan during meditation. Novices and monks must master a series of Kōans. To determine whether they have actually succeeded, the student is instructed to find a key word (jakugo) appropriate for the corresponding Kōan. Depending on the temple affiliation, the order of the Kōans to be mastered, along with their corresponding jakugo, is fixed. Over the centuries, this "curriculum" has solidified. As an inner experience, this realization is not to be confused with an intellectual grasp of the problem. It is not an interpretation of the Kōan or an explanation. This happens occasionally in the Teishō. The student's individual insight would often seem even more meaningless to the layman than the Kōan itself. From the student's reaction to the Kōan, the experienced master can tell whether the student is making progress on the path of Zen, or whether he is persisting in illusion and error. The Zen master's written or oral comments on a Kōan are called Agyō (granted words).
This method of practice and examination is used primarily in the Rinzai direction of Zen.
There are five "classes" of Kōans that serve different functions.
A: The term "kōan" refers to a grouping of related questions and answers which present a paradox.
A: Kōans are made up of related questions and answers that are difficult to understand or explain easily.
A: The purpose of a kōan is to challenge the mind and encourage deep reflection.
A: No, kōans cannot be understood or explained easily.
A: Yes, a kōan can have a hidden meaning, like a special type of metaphor.
A: Yes, "the sound of one hand clapping" is an example of a kōan that is a metaphor with a hidden meaning.
A: The term "kōan" originated in China and was later adopted by Korean and Japanese Zen Buddhism.
