What then did Huangbo teach, if there is nothing to be taught? The answer seems to be to stop seeking, for only then does wisdom come. Furthermore, to study a doctrine of nonattachment puts you in the compromising position of becoming attached to nonattachment itself.
If you students of the Way wish to become Buddhas, you need study no doctrines whatever, but learn only how to avoid seeking for and attaching yourselves to anything Relinquishment of everything is the Dharma, and he who understands this is a Buddha, but the relinquishment of ALL delusions leaves no Dharma on which to lay hold.
But just how does Huangbo manage to practice what he preaches?
. . . Most students of Zen cling to all sorts of sounds and forms. Why do they not copy me by letting each thought go as though it were nothing, or as though it were a piece of rotten wood, a stone, or the cold ashes of a dead fire? Or else, by just making whatever slight response is suited to each occasion.
He finally gives up on words entirely, declaring, that none of the terms he has used has any meaning.
As John Wu has pointed out, in a sense Huangbo had come back full circle to the insights of Zhuangzi: good and evil are meaningless; intuitive knowledge is more profound than speech-bound logic; there is an underlying unity (for Zhuangzi it was the Tao or Way; for Huangbo, the Universal Mind) that represents the ineffable absolute.
In effect, Huangbo laid it all out, cleared the way, and defined Chan once and for all. The Perennial Philosophy was never more strongly stated. The experimental age of Chan thus drew to a close.
It was time now for Chan to formalize its dialectic, a task taken care of by Huangbo's star pupil, Linji