Master Kuei-Feng, also, said that when shallow and deep stages of Ch'an are referred to and that when a person chooses to practice the deep ones because he looks down on the shallowstages and then finds a way to do so, what he engages in is called heterodox Ch'an. Holding to cause and effect and practicing with like and dislike are known as Worldly-People Ch'an. However, when only the illusion of the personal self has been eliminated through Enlightenment but not that of the self-nature of dharmas (things), this is called Hinayana Ch'an. On the other hand, when the ego and all dharmas are enlightened, this is called Mahayana Ch'an. Here, the self-nature of one's self and the self-nature of everything else, or all dharmas, are known to be unreal. If one's own mind is suddenly enlightened, it is in its original purity, free of defilement and not outside the stream. This mind is the Buddha, and practicing in this manner is called Supreme Ch'an.

The Sixth Patriarch, Hui-Neng, described sitting Ch'anby stating that being without obstacles in the Dharma and being beyond all ideas of good and evil, without a single thought arising, is called sitting,whereas seeing into the stillness of one's Original Nature is called Ch'an.Regarding Ch'an-Ting,he said that the absence of external form (i.e., no object) is Ch'an,and to be free of the confusion of thought (i.e.,no subject) is Ting.Furthermore,  he said that if one grasps the forms (the apparent objects outside), this is evidence of a confused mind and adds to the confusion of what the mind conceives of as being inside. If one is no longer attached to objects and to there being an outside, then there is no longer any such confusion of mind. Original Nature is pure and still, but is disturbed by thinking and, it follows, by objects. When there are no things, no outside and no confusion in the mind, that is real Ting.The Sutra of Bodhisattva Discipline is a bit more succinct. There, it simply says that originally your own nature is clean and pure.

Observing The Mind 
We are ordinarily concerned with things that are conceived of as being outside of us, or, essentially, the objects of our thoughts; and we never think of observing the place within, as it were, whence thoughts seem to arise. By looking inward at the source of thought, the workings of your mind are still evident but are no longer so commanding, and a more and more passive sort of observation develops that reduces false thought and can help to reveal your own True Nature. In all Mahayana sutras, it can be seen that Prajna (Wisdom) must be accompanied by Universal Illumination. In one such sutra entitled Observing the Ground of the Mind,it is stated that one who observes the mind can be liberated but that one who does not is always bound by birth and death. Along somewhat similar lines, one finds in The Sutra of Nirvana that Supreme Dhyana is described as observing the nature of  the mind. Chih-Kuan,in Buddhadharma, is translated as either Dhyanaand Wisdom (Ting-Hui)or Stillnessand Illumination.In The Maha-Chih-Kuan the stillness of Dharma Nature is called Chih,and stillness with illumination is called Kuan;and it concludes, therefore, that Chih-Kuanis the supreme method for purifying the mind. There are, however, many ways to practice Chih-Kuan.Just to mention a few, there are Deep and Shallow, Sudden and Gradual, Cultivation and Principlesand Complete and Incomplete;and to complicate matters even further, there are three different categories of Chih-Kuanin the T'ien T'ai tradition: gradual, unfixed and perfect.

Gradual Chih-Kuan 
In The Commentary on the Dhyana Paramita of Gradual Chih-Kuan,  practice is described as being shallow at first and deep later, which implies a gradual development. Understanding, however, is said to come suddenly.

Unfixed Chih-Kuan 
Unfixed Chih-Kuan, also known as The Six Wonderful Dharma Gates,is sometimes described as the step-by- step methodleading to sudden understanding. Here, practice is gradual at first and then sudden.

Perfect Chih-Kuan 
In The Maha-Chih-Kuan, it says that in Perfect and Sudden Chih-Kuan, all conditions and reality are merely three contemplations in one mind, and that there is only sudden understanding and action, with no distinction as to when it began or as to how it progressed thereafter.

The practices of The Maha-Chih-Kuan method are thorough, assuredly, but are too subtle to be done without the aid of an accomplished teacher. However, until such time as the reader may discover such a teacher, he might practice the following effective method of observing the mind. Sit comfortably in the lotus position or in any other position that is suitable for you. Lay down all things, and even give up the thought of laying everything down. In this way, thinking of neither good nor evil, close your eyes gently and lightly observe where your thoughts seem to issue from. This permits you passively to be aware of your false thoughts as they suddenly come and just as suddenly go, neither grasping at them nor driving them away; thus, in time, you can come to understand profoundly that false thought  has no  self-nature (is empty)  and that it is originally void. When false thought is then illuminated by your mind, a stillness becomes evident, which then becomes suchness.Then if another thought suddenly arises, using the same approach, just observe lightly to see where the thought seems to come from. Do this at least once a day for at least half an hour.

If you continue to reinforce your knowledge of Buddhadharma, as well, through reading and finding people who are inclined to hear what you might have to say about Buddhism or practice, then, over a period of time, this meditation can help reduce false thought (known as using wisdom to support Ting)and increase the power of illumination (known as using Ting to beget wisdom).If you continue in this way, you will, eventually, be able to sit without a single thought arising.  When there is awareness, with no dwelling and no grasping, the source of mind is void and still. Then, Wisdom (Prajna) and Original Nature respond as one from moment to moment. In The Hand-Flower Sutra, it states that when you observe the mind, you see the birth and death of thought after thought as having the quality of being magical and unreal. The subject of Wisdom is Prajna, which is like saying that Prajna is Wisdom, while its object is ignorance (confusion or false thought). The perfume of Prajna is then said to permeate ignorance more and more until there is just Prajna and a return to Original Nature. Whether walking, sitting or lying down, one should always be aware of the Substance (stillness) of Original Nature.

The function of illumination is Enlightenment, which is sometimes referred to as right thought about reality.It is like a pearl that emits light and, thereby, also illuminates the substance of the pearl. If a false thought arises in an illuminated mind, it vanishes as quickly as a snowflake in a blazing furnace. Then, even strong habits no longer present any obstacles. With such practice, your Original Nature appears stronger and stronger. There should be no needor intentionto have illumination, because need and intention stand in the way of its ever coming about. When there is real illumination, there is no longer any involvement with words. Then, mind is no-mind. Then, there is simply Suchness.Without thought, there are no conditions; and Original Nature, known directly, isreality. However, even if you can concentrate on one thought and observe the mind for just a moment or two, you still have benefited by knowing Prajna, and have, thereby, planted the seed of Bodhi. In The Lankavatara Sutra, it says that you should rely fully on the teachings and then find a quiet place where, practicing free of all doubt, there can be Enlightenment. In The Sutra of Complete Enlightenment, it says that all Tathagatas arise from the ground cause of correct practice; and so, again and again, proper understanding and right practice are advised.

Conclusion 
We have seen that there are many ways to bring about meditation in the Buddhist tradition and that they can bestow upon a practitioner all-around emotional, mental and physical health, enabling him to gain Enlightenment and, thereby, benefiting both himself and others. There is the proviso, however, that even though sitting practice can promote good health, health is beneficial only temporarily; because, no matter how long you live, you must finally die. In The Sutra of Complete Enlightenment, it says that since time without beginning,  all sentient beings have been mired in ignorance. In their confusion they have mistaken the four elements (earth, water, fire, air) for their bodies and the shadows of the data of their six conditioned senses for their minds. The aim, then, is to be free of those delusions, going from confusion to Enlightenment. To keep that aim alive, it is important to use sutras and anything else that helps to clarify Buddhadharma and to continue to practice discipline and concentration in order to develop expert meditation so that Prajna can arise.