The following are Yang Cheng Fu's 10 principles on tai chi.
1. Straightening the head
Stand straight and hold the head and neck naturally erect with the mind concentrating on the top. Do not strain or be tense otherwise the blood and vital energy cannot circulate smoothly.
2. Correct position of the chest and back
Keep the chest slightly inward, which will enable you to sink your breath to the dan tian (lower belly). Do not protrude your chest, otherwise you will feel uneasy in breathing and somewhat top heavy.
3. Relaxation of waist
For the human body, the waist is the dominant part. When you relax the waist, your two feet will be strong enough to form a firm base. All the movements depend on the action of the waist.
4. Solid and empty stance
It is of primary important to distinguish empty and solid. If you shift the weight of the body to the right leg, then the right leg is solidly planted on the ground and the left leg is in an empty stance. Only in this way can you turn and move your body adroitly and without effort, otherwise you will be slow and clumsy in your movements and not able to remain stable and firm on your feet.
5. Sinking of the shoulders and elbows
Keep your shoulder in a natural relaxed position. If you lift your shoulders, the qi will rise and the whole body will be without strength. You should also keep the elbows down, otherwise you will not be able to keep your shoulders relaxed and move your body with ease.
6. Using the mind instead of force
The whole body is relaxed and there is not an iota of stiff or clumsy strength in the veins or joints to hinder the movement of the body so the energy will circulate unobstructed.
Co-ordination of upper and lower parts
The root is in the feet, the force is launched through the legs, controlled by the waist and expressed by the fingers; the feet, legs and waist form a harmonious whole. When the hands, waist and legs move, the eyes should follow their movements. This is meant by the co-ordination of the upper and lower parts. If any part should cease to move, then the movements will be disconnected and fall into disarray.
8. Harmony between the internal and external parts
The focus is on the mind and consciousness. With the tranquility of the mind, the movements will be gentle and graceful.
9. Importance of continuity
One focuses the attention on the mind instead of the force and the movements from the beginning to the end are continuous and in an endless circle.
10. Tranquility in movement
The movement is blended with tranquility and while performing the movements, one maintains tranquility of mind.
~ Yang Style Tai Jiquan by Yang Zhen Duo