The Koan

The main thing is to shut off all your sense-organs and make your consciousness like a block of wood. When this block of wood suddenly starts up and makes a noise, that is the moment you feel like a lion roaming freely, completely unencumbered, or like an elephant that crosses a stream immune to its swift current. At that moment, there is no fidgeting, nothing doing, just this and no more. Says P'ing-t'ien, the Elder:

The celestial radiance undimmed,
The norm lasting for ever more;
For him who entereth this gate,
No reasoning, no learning.

You should know that it is through your seeing, hearing and thinking that you enter upon the path, and it is also through seeing, hearing, and thinking that you are prevented from entering…. If you want, however, to be the free master of yourself by doing away with your seeing, hearing, and thinking, stop your hankering monkey-like mind from doing mischief; keep it quietly under control. Keep your mind firmly collected regardless of what you are doing — sitting or lying, standing or walking, remaining silent or talking. Keep your mind like a line stretched taut — do not let it slip out of your hand. Just as soon as it slips out of your control, you will find it in the service of seeing, hearing, and thinking. In such a case is there any remedy? What remedy is applicable here?

A monk asked Yun-men, "Who is the Buddha?" "The dried-up dirt-cleaner." [was his reply]. This is the remedy. Whether you are walking or sitting or lying, let your mind be perpetually fixed on this "dirt-cleaner." The time will come when your mind will suddenly come to a stop like an old rat who finds itself in a cul-de-sac. Then there will be a plunging into the Unknown with the cry, "Ah, this!" When this cry is uttered, you have discovered yourself. You will find at the same time that all the teachings of the ancient worthies expounded in the Buddhist Tripitaka, the Taoist Scriptures, and the Confucian Classics, are no more than commentaries upon your own sudden cry, "Ah, this!"

– Tai-hui