Originally Ch'an masters did not use any recorded hua-t'ous. These simply occurred spontaneously. Later, these happenings were recorded as "kung-ans, " and handed down to later generations to "investigate." In the ancient days the masters just guided the disciples to the point where hua-t'ous occurred spontaneously. Later generations used these recorded kung-ans when they could not generate the questions by themselves. But kung-ans or hua-t'ous can produce Great Doubt only if one's mind is already in a unified state, only when he has already a strong foundation of practice. Otherwise, it can become just a mechanical repetition, producing no useful effect whatsoever. And very likely the practitioner will be using reasoning, knowledge, and experience to find an answer. This is neither the Great Doubt, nor is it investigating Ch'an.

So it is possible to practice kung-ans before your mind is unified and concentrated, but it will not produce the Great Doubt. I will not give a disciple a kung-an in the very beginning. I will wait until he has a certain foundation before I will give him one or help him generate his own.

The object of the hua-t'ou is to cause sudden enlightenment. If one were to practice hua-t'ou with a scattered mind, then it would be similar to reciting a mantra. This is not to negate the usefulness of mantras. If you recite a mantra with a concentrated mind, you can enter samadhi. If you merely recite a hua-t'ou instead of "investigating" it, you can also enter samadhi. And in samadhi a certain wisdom can be generated. But this wisdom is very limited. The purpose of Ch'an is to be suddenly enlightened to Buddha nature. What is Buddha-nature? What is enlightenment? It can only be known from the actual experience. Samadhi itself cannot produce wisdom. You must have Great Doubt which leads to a cataclysmic experience.