If the master rings a bell to dismiss the student, this means the student's understanding is not right and that their work with the koan must continue. It is typically held twice a day in a monastery, though during a week-long sesshin sanzen may take place as often as four times in one day.
If the master rings a bell to dismiss the student, it signifies that the student's comprehension is inadequate and their work with the koan must continue. It is typically practiced twice daily in a monastery, though during a week-long retreat, sanzen may occur as often as four times per day.