口伝

The term refers to the transmission of knowledge, skills, or secrets exclusively by word of mouth. Unlike a simple oral explanation, it carries a strong connotation of tradition, lineage, and exclusivity. It is most frequently used in the context of traditional Japanese arts, martial arts (Budo), or religious rites where certain "secret" techniques (hiden) are passed from a master to a chosen disciple to prevent the knowledge from leaking to outsiders.

In modern usage, it is rarely used for casual conversations or instructions. Instead, it evokes an image of a sacred or disciplined transfer of wisdom that is intentionally kept out of written records to preserve its authenticity or exclusivity.

Compared to "kuden" (口伝), the word "densho" (伝承) is broader and refers to general folklore or traditions passed down through generations, whereas "kuden" specifically emphasizes the act of speaking and the direct relationship between the teacher and the student.