There is a beginning, a middle and an ending to all of the Tai Chi postures. This will be very important for students to know when they start to understand movement and energy. Once the students have learned Tai Chi at its most basic level, and have been doing Tai Chi for a few years, they will develop, what I like to call a Tai Chi body, where they start to understand the concept of sung - to sink and root while releasing tension.
As students advance they are taught that there are different levels that they will progress through until eventually they arrive to the fifth level, where the internal movement is in complete harmony with the external movement. The five levels in Tai Chi Chuan are:
Level 1 - The introductory level where students are taught each individual posture and work on the gross motor movements in a very mechanical manner.
Level 2 - The basic level where students start to learn to flow these postures together looking and feeling a lot more like Tai Chi. Many people including some teachers stay at this level and look very good when performing Tai Chi. Unfortunately, you can never get the true essence of Tai Chi Chuan without progressing to the next levels.
Level 3 - Applying the concepts and principles of yin and yang. All states are always changing from yin to yang and from yang to yin. There is never a double weighted state. One hand should always represent yin energy while the other represents yang energy.
Level 4 - The opening and closing of each posture. Each posture opens (expands) and closes (sinks) as well as the entire form, when done properly, opens and closes.
Level 5 - The highest level where we internalize the movements and harmonize the external movements with the internal chi, thus creating much smaller movements. The external movements become very small, to match the internal movement of chi. The movements have become internal and no longer actually show externally, only a very well trained eye will see these internal movements that only slightly show externally. This is because the points of change between yin and yang and yang and yin have become empty. This is the beginning or end of each movement. The student should actually feel this emptiness at the end of each move and just before they begin the next move. So that the empty movements are both yin and yang and change into each other depending upon what part of the movement they are doing.
Today many Tai Chi Chuan teachers focus only on the health aspects of the art and not on the way it was intended to be, a true Chinese martial art. At best they can only bring their students up to a good level 2. In order for the student to gain the real, true, deep benefits that Tai Chi Chuan was created for, they must progress to upper levels and have a teacher that can explain and demonstrate those levels, giving the students the opportunity to learn the complete art of Tai Chi Chuan.