Perhaps the most thoughtful Zen philosopher of them all was Huang-po (d. 850?), who picked up where the earlier teachers had left off and brought to a close the great creative era of Ch'an. He also stood at the very edge of the tumultuous watershed in Chinese Buddhism, barely living past the 845 Great Persecution that smashed the power of all the Buddhist schools except that of the reclusive Southern Ch'anists.
Originally named Hsi-yun, the master moved at a young age from his birthplace in present-day Fukien to Mt. Huang-po in the same province, the locale that gave him his Ch'an title. His biography declares that his voice was articulate and mellifluous, his character open and simple.1 He later decided to make a pilgrimage to see the famous Ma-tsu, but when he arrived in Kiangsi he was told that the master had died.2 Po-chang Huai-hai was still there, however, and consequently Huang-po settled down to study with him instead.
Huang-po is known to us today primarily through the accident of having a follower obsessed by the written word. This man, Pei Hsiu, was also a high Chinese official who served as governor in two of the provinces where Huang-po at various times resided. He studied under Huang-po both times (all day and night, so he claimed) and later produced an anecdotal summary of the master's teachings now known as _On the Transmission of Mind_.3 This document was extensive, representing one of the most detailed descriptions of an early master's thoughts. Pei Hsiu also reports in his preface (dated 858) that he sent his work back to Kuang T'ang monastery on Mt. Huang-po to have it authenticated by the old monks there who still remembered the sayings of the master.4
By the time of Huang-po the issue of "gradual" versus "sudden" enlightenment was decisively resolved in favor of the latter. He therefore turned instead to two major remaining questions: 1) how enlightenment fits into the mental world, and 2) how this intuitive insight can be transmitted. Before he was through he had advanced these issues significantly and had laid the philosophical basis for the next phase of Ch'an in China--to be dominated by the school of his pupil Lin- chi.
Huang-po struggled with a fundamental dilemma of Ch'an: how the wordless wisdom of intuition can be passed from generation to generation. Enlightenment necessarily has to be intuitive, and that means traditional teaching methods are useless. There are no conceptual formulations or "concepts." It is by definition wordless. It has to be realized intuitively by the novice, by himself. The masters had isolated a type of knowledge that words could not transmit. It was this transmission of wordless insight, of Mind, that obsessed Huang-po.