A private interview between a student and a Zen teacher or master. The format and length of the interview, and whether it revolves around koan work or involves another kind of exchange, varies depending on the teacher. As a general rule, dokusan pertains more to a student’s personal practice and experience than it does academic, theoretical matters. Theoretical questions are usually discouraged but often permitted (again very much of this depends on the teacher). Dokusan is a critical element of Zen training and an important part of sesshin, though it is by no means limited to sesshin: some modern teachers have expanded the practice of dokusan to include communication by telephone and e-mail.