Progress in Chen T'ai Chi by Paul Chou and Scott Hunter 1997
First Stage Learn the Form

We begin by learning the movements that comprise the form. Initially we check our balance and the form at the end of the 64 named movements. As we become familiar with the form we pay attention to the pace and rhythm of the basic form. We become aware of the path of each joint in space and time and we sense our weight distribution and stability from moment to moment. In this stage we emphasize the awareness of the prescribed configuration of the skeletal frame and the shifting distribution of our weight. If we don't get carried away with the drama, we can check the line of thrust which extends from the rooted foot through the hand and out through the imagined opponent. We do this, initially, at the end of each of the named movements.
Stage Two Mastering Forward Kinematics

Mastering Forward Kinematics refers to movement in which the movement of each portion of the body is generated from, and is consistent with, the movement of the predecessor part. It is optimized movement that allows the body to perform a chosen action most easily and powerfully. The normal order of movement consistent with forward kinematics is:

Foot, Ankle, Shin, Knee, Thigh, Hips, Trunk, Shoulder, Upper Arm, Elbow, Forearm, Wrist, Hand, Fingers through the tips and out to far away

Example. If the action is to move the right hand to a particular point, the movement of the whole body is generated from the tan tien: aligning the hips and placing the feet and legs in the optimum position to support the movement of the upper body. In turn, this allows the upper body to remain erect and the shoulders, elbows and wrist to rotate within their optimal range of motion. Every joint has a portion of its total range of motion where the associated muscles can easily hold the joint in place and be most effective in rotating it. The movement of the hands is optimized when every part of the body moves within its optimum range completing the movement simultaneously. Thus, by this coordination, the power of the whole body is present in the movement of the hand.

In some traditions forward kinematics has been mastered by the guidance of the principles of T'ai chi and postural checkpoints.

The most important principle for this mastery is Relax the body. By draining tension from the whole body and using the minimum energy needed to create the form we approach the optimum configuration, the same configuration sought by mastering forward kinematics. The situation is akin to solving a problem in the physics of rigid body motion. We can use energy methods or we can write the equations of motion and solve them.

In Chen Style, mastering forward kinematics is made explicit. Cultivate a sense of the line of thrust from the rooted foot through the thrusting leg, the stable erect trunk, the comfortably curved arms through the point of contact and out to far away. Moment by moment, check the integrity of the skeletal frame. Is the frame optimized for this action right now? And Now?

This overall movement that is self directed and optimized is named Yang.
Stage Three Mastering Inverse Kinematics

This stage presupposes mastery of the form and of optimized self directed movement consistent with forward kinematics.

In this stage, the configuration is optimized in response to the pressure of an opponent, physical or imagined. Contact with the opponent is continuous and finely controlled. No matter how the opponent moves the contact remains even and unbroken. Yet the movement has at all times the qualities of integrity and optimized configuration consistent with forward kinematics. In this stage Pushing Hands practice becomes important. Pushing Hands directly tests mastery of inverse kinematics. We check our contact and our configuration from moment to moment as we move with our opponent: Is the pressure like ''four ounces of butter'' while moving in and ''As light as ashes brushing his clothes'' when our opponent comes toward us? Can we feel the line of thrust from the rooted foot up through the point of contact? Is every joint and element of the body in its range of optimum function?

We can also ask: Given my configuration and my opponents configuration at this instant, where does the practice of the form teach me to go? This last question leads back to the continuing practice of the form. This practice takes on another quality at this stage. The continuous presence of an imagined band of opponents supplies a constant source of pressure. Harmonizing with these pressures while maintaining integrity of form is named YIN.
Stage Four Mastering Speed and Force

Not only do we not know where the next challenge will come from we do not know its size or speed. Having mastered inverse kinematics at our ideal practice speed, we now play at this mastery at all speeds and with all different weight and style of opponents. This is the time of travel for study. We approach other teachers and students of martial arts and learn with them where we flow and where we get stuck. What we can handle and where we jump out of harmony into old habits and reactive patterns. If our attitude is humble and friendly, we will encounter much more harmony in our study at this stage.

There is another aspect in mastering speed and force. At earlier stages in our practice we have become increasingly clear and efficient at the form and have learned to move and turn quickly. But we have used the large circles of the form to learn the spiral and circular style of movement. Now we can condense these circles and find that our movements take on an explosive power. A partial explanation is that in condensing the circle we reduce our rotational inertia but the rotational momentum is unchanged and thus the speed of the movement increases greatly.
Stage Five Mastery of Time and Space

In this stage we emphasize the field that the body plays in. The awareness that has given us control over the flow of chi in our system is expanded to our surroundings. When the awareness is not fixated on the body we enter that which is timeless. The rules for how bodies interact in time and space have a different quality. There is freedom.
Stage Six Ordinary Practice

We continue to practice. The circle of our movement condenses to a radius too small to see. But every movement is made with integrity. To an opponent watching the yin and yang of our movement there is no fluctuation. Are we rooted and flowing out? or are we following and yielding? At any moment we are either. We are both. The Yin and the Yang of our movement is completely interpenetrated and nourish each other. Such harmony invites agression to pause. This harmony invites any rough nature to quiet itself and to enjoy itself in good company.
It is all right here.

We progress from the mechanical to the energetic and thence to the spritual. From large clear movements to subtle. From the experience of separation and conflict to harmony. Yet the goal, the end, is present here and now, right from the beginning of our practice. We feel it when we experience joy and peace in our practice even as we learn the initial movements. How could it be otherwise? We are only discovering our nature which is one with all of nature,. It is unchanged by our ignorance and welcomes our discovery.