Kensho is a Japanese term for enlightenment experiences, most commonly used within the confines of Zen Buddhism. It generally refers to the realization of nonduality of subject and object. Frequently used in juxtaposition with satori, there is sometimes a distinction made between the two in that some consider satori to be qualitatively deeper.
Kensho itself has been said to be a blissful realization where a person’s inner nature, the original pure mind, is directly known as an illuminating emptiness which is dynamic and immanent in the world. Kenshō experiences are tiered, in that they escalate from initial glimpses into the nature of mind to an experience of emptiness.
Working towards this realisation is usually a lengthy process of meditation and introspection under guidance of a Zen or other Buddhist teacher, usually in intensive retreats. The methods used differ depending upon the tradition and practice. Soto tends towards a gradual approach preferring to let the experiences happen on their own while Rinzai tends toward the use of Koans or a set Koan question as a technique to bring the experience sooner.
Which methods are more appropriate for any given student are made by which lineage of Zen the student practices as well as what seems most appropriate by the student’s teacher. It should be noted that the Kensho experience is not limited to Japanese Zen Buddhism traditions and occurs in many traditions as well as outside of Buddhist practice.
Kensho may also be spontaneous, upon hearing or reading some significant phrase, or as result of a profound dream. For example, Zen lore describes the Sixth Patriarch Hui Neng’s spontaneous experience of kensho upon hearing a phrase of the Diamond sutra.
Koans are a technique that can be used as meditation aids, particularly in the Rinzai tradition. For example, one koan is known as ‘Who am I’, since it is this question that guides the enquiry into one’s true nature. The realization that there is no ‘I’ that is doing the thinking, but rather that the thinking process brings forth the illusion of an ‘I’, is a step on the way to Kensho.
It is not unusual for various hallucinations and psychological disturbances to arise prior to true kensho. These are referred to as makyo. Distinguishing these delusions from actual kensho is the primary function of the teacher, as the student may be erroneously convinced they have realized kensho.