What is it that is transmitted from master to disciple, generation after generation? It is Buddha-mind. When a person has eliminated his vexations, that is called “getting the Buddha-mind.” We also use the phrases “seeing one’s self-nature, ” or “seeing one’s original face.” The person who has entered the Path has done so because he wants to break the endless cycle of suffering. At the moment of enlightenment he is clear of vexation and has received the Buddha-mind. So “transmission” means both that the student has had a Buddha-mind experience and that the experience was recognized by a master. Although it is said that the Buddha-mind has been “transmitted” from Sakyamuni to master to disciple, it is really the disciple who, through faith and practice, has come up with that Buddha-mind. To confirm the transmission, there must be an experienced master who can recognize the student’s achievement. There are not many formal records of Ch’an retreats, but a few famous cases come down from the Sung Dynasty. In one of these, Master Ta-Hui held a retreat in which thirteen out of fifty-three became enlightened. Another master, Yuan-Wu, transmitted to eighteen disciples in one night. This gives you some idea of the power of the Ch’an retreat in the hands of a great master.
Because the traditional retreat had many participants, there was little opportunity to speak with the master. In fact, the master would usually come into the hall only to say a few words. Most disciples would not dare ask for a private interview unless he had an experience he wanted to have affirmed. In modern times, the Ch’an master has been more accessible. In Japan the dokusan, or interview, is actually required by many masters. In any event, it is in the interview that recognition usually takes place. More often than not, the student is not confirmed and sometimes even receives a stinging rebuke or a beating. This is done not to punish but to provoke the student to greater effort or to break through obstructions, and is used by the master according to his perception of the student’s state of mind. To a Ch’an master, even the way a student prostrates can show a presence or lack of genuine achievement.
In Sakyamuni’s time there were disciples who got enlightened but didn’t know it, and others who thought they did, but, in fact didn’t. It was necessary for Sakyamuni himself, or one of his major disciples, to recognize and confirm the disciples. Therefore, to attain the Buddha-mind and to be confirmed are strong reasons for participating in retreats.
— Getting The Buddha Mind by Master Sheng-Yen (page 12-13)