The great Ch'an Master, whose Dharma-name was Hsi Yun, resided below Vulture Peak on Huang-Bei Mountain, which is in Kao-An County in Hung-Chou.  He was a major disciple of Ts'ao-Ch'i, the Sixth Patriarch, and the Dharma-son of Pai-Chang.  He admired the Supreme Mahayana Vehicle and sealed it without words, teaching the transmission of Mind only and no other Dharma whatsoever.  He held that both Mind and substance are void and that the interrelationships of phenomena are motionless.  Thus, everything is, in reality, void and still like the radiant light of the great sun in the sky, shining brightly and purely throughout the world.  If one has attained this understanding, he holds no concept of duality ? such as new versus old or shallow versus deep ? in his mind.  If one has attained this understanding, he does not attempt to explain its meaning, nor does he hold biased views, one way or another, regarding particular sects.  The Master just pointed out that " It is!" alone is the correct  understanding.  So, even allowing a single thought to arise is wrong.  He made clear that the profound meaning beyond words is the Tao, which is subtle and the action of which is solitary and uniform.

Thus, many disciples came to him from the four directions, most of them becoming enlightened merely upon first seeing the Master; and usually a company of more than one thousand disciples accompanied him at any one time.

In the second year of Hui-Ch'ang (842 C.E.), I stayed in Chung-Ling, inviting the Master to come to the city from the mountain.  While residing together at Lung-Hsing Temple, I asked the Master, every day, to transmit the Dharma to me.  Also, later, in the second year of Ta-Chung (848 C.E.), I stayed in Wan-Ling, again inviting the Master to the city.  At that time, while residing together at K'ai Yuan Temple, I received Dharma from the Master every day.  A few years later, I made a record of the Dharma that the Master had transmitted to me, but I could recall only a small portion of it.  Nevertheless, I regard what is set down here to be the genuine Mind-Seal Dharma.  Initially I had some reservations about making this Doctrine public, but, afterwards, feang that this wonderful and profound Teaching might not be available to or known by future truth-seekers, I decided to publish it.

With this in mind, I have sent the manuscript to the Master's disciple, Tai-Chou Fa-Chien, asking him to return to Kuang-T'ang Temple, on the ancient mountain, and discuss my record with certain elder monks and other Sangha members to determine how much it agrees with or how much it differs from what they themselves had heard and learned from the Master.