by Yang Cheng-fu (1883 - 1936) as researched by Lee N. Scheele

1. Head upright to let the shen [spirit of vitality] rise to the top of the head. Don't use li [external strength], or the neck will be stiff and the ch'i [vital life energy] and blood cannot flow through. It is necessary to have a natural and lively feeling. If the spirit cannot reach the headtop, it cannot raise.
2. Sink the chest and pluck up the back. The chest is depressed naturally inward so that the ch'i can sink to the tan t'ien [field of elixir]. Don't expand the chest: the ch'i gets stuck there and the body becomes top-heavy. The heel will be too light and can be uprooted. Pluck up the back and the ch'i sticks to the back; depress the chest and you can pluck up the back. Then you can discharge force through the spine. You will be a peerless boxer.
3. Sung [Relax] the waist [hip joints]. The waist is the commander of the whole body. If you can sung [relax] the waist, then the two legs will have power and the lower part will be firm and stable. Substantial and insubstantial change, and this is based on the turning of the waist. It is said "the source of the postures lies in the waist. If you cannot get power, seek the defect in the legs and waist."
4. Differentiate between insubstantial and substantial. This is the first principle in T'ai Chi Ch'uan. If the weight of the whole body is resting on the right leg, then the right leg is substantial and the left leg is insubstantial, and vice versa. When you can separate substantial and insubstantial, you can turn lightly without using strength. If you cannot separate, the step is heavy and slow. The stance is not firm and can be easily thrown of balance.
5. Sink the shoulders and elbows. The shoulders will be completely relaxed and open. If you cannot relax and sink, the two shoulders will be raised up and tense. The ch'i will follow them up and the whole body cannot get power. "Sink the elbows" means the elbows go down and relax. If the elbows raise, the shoulders are not able to sink and you cannot discharge people far. The discharge will then be close to the broken force of the external schools.
6. Use the mind instead of force. The T'ai Chi Ch'uan Classics say, "all of this means use yi [mind-intent] and not li." In practicing T'ai Chi Ch'uan the whole body relaxes. Don't let one ounce of force remain in the blood vessels, bones, and ligaments to tie yourself up. Then you can be agile and able to change. You will be able to turn freely and easily. Doubting this, how can you increase your power?
   
   The body has meridians like the ground has ditches and trenches. If not obstructed the water can flow. If the meridian is not closed, the ch'i goes through. If the whole body has hard force and it fills up the meridians, the ch'i and the blood stop and the turning is not smooth and agile. Just pull one hair and the whole body is off-balance. If you use yi, and not li, then the yi goes to a place in the body and the ch'i follows it. The ch'i and the blood circulate. If you do this every day and never stop, after a long time you will have nei jing [real internal strength]. The T'ai Chi Ch'uan Classics say, "when you are extremely soft, you become extremely hard and strong." Someone who has extremely good T'ai Chi Ch'uan kung fu has arms like iron wrapped with cotton and the weight is very heavy. As for the external schools, when they use li, they reveal li. When they don't use li, they are too light and floating. Their jing is external and locked together. The li of the external schools is easily led and moved, and not to be esteemed.
7. Coordinate the upper and lower parts of the body. The T'ai Chi Ch'uan Classics say "the motion should be rooted in the feet, released through the legs, controlled by the waist and manifested through the fingers." Everything acts simultaneously. When the hand, waist and foot move together, the eyes follow. If one part doesn't follow, the whole body is disordered.
8. Harmonize the internal and external. In the practice of T'ai Chi Ch'uan the main thing is the spirit. Therefore it is said "the spirit is the commander and the body is subordinate." If you can raise the spirit, then the movements will naturally be agile. The postures are not beyond insubstantial and substantial, opening and closing. That which is called open means not only the hands and feet are open, but the mind is also open. That which is called closed means not only the hands and feet are closed, but the mind is also closed. When you can make the inside and outside become one, then it becomes complete.
9. Move with continuity. As to the external schools, their jing is the Latter Heaven "brute" jing. Therefore it is finite. There are connections and breaks. During the breaks the old force is exhausted and the new force has not yet been born. At these moments it is very easy for others to take advantage. T'ai Chi Ch'uan uses yi and not li. From beginning to end it is continuous and not broken. It is circular and again resumes. It revolves and has no limits. The original Classics say it is "like a great river rolling on unceasingly." and that the circulation of the jing is "drawing silk from a cocoon " They all talk about being connected together.
10. Move with tranquility [Seek stillness in movement]. The external schools assume jumping about is good and they use all their energy. That is why after practice everyone pants. T'ai Chi Ch'uan uses stillness to control movement. Although one moves, there is also stillness. Therefore in practicing the form, slower is better. If it is slow, the inhalation and exhalation are long and deep and the ch'i sinks to the tan-t'ien. Naturally there is no injurious practice such as engorgement of the blood vessels. The learner should be careful to comprehend it. Then you will get the real meaning.