Too many students learn tai chi or Baguazhang and think that that's all there is to the form. That's the way that they must do it forever more. However, nothing could be further form the truth, other than I can fly. When one performs any internal form, the movements will be self-adjusting continuously. A minute turn of the foot here or a widening of the step there will help you to maintain internal balance thereby gaining all of the wonderful health benefits from this form.
When one begins to learn tai chi, this process will be a conscious effort to adjust the feet and hands in order to maintain physical balance. After some time however, this will be a sub-conscious thing where both are balanced without your even knowing that you are doing it.
For instance, it's alright to move your foot after it has been placed for the posture of Brush Knee and Twist Step, or it is OK to change the position of your hands in the Posture of Bat Falls To earth in Baguazhang in order to make for amore balanced posture. It is, after all, the postures that cause everything to happen and depending upon your own physical state at any given time, these postures will change slightly to accommodate this. My students often tell me that when I do the form with them or do it while they watch, it seems to be different every time with an unknown quality each time. This is because I do the form differently every time depending upon the time of day, what my own internal Qi is doing at that time and whether I am in a Yang or Yin mode.
The whole form is changing naturally anyway as you change your weight from foot to foot or within the same foot in order to satisfy one of the most important classics of "there must be weight change with every hand movement". This is probably the most important classic as this is true Yin and Yang. Postures that SEEM to be standing still on one foot for instance, aren't, as the weight is still changing from heel to ball of that same foot as the hands execute the movement.
The Energy is rooted in the foot, moves through the thighs, is directed by the Waist and manifests in the hands and fingers (wrists).
This saying is also a very important classic saying as it tells us that the wrists must gather energy from the feet and manifest that energy in the hands. What begins as a big open movement in the feet, ends up as a small, very powerful spiralling movement in the wrist. It's like a volcano as the lava works its way up to the opening, it comes up with so much 'slow' energy but as it nears the opening, it explodes forth with tremendous power. And it's the same with the wrists as they take this tsunami that begins in the feet and explodes it out of the hands.
So this aspect will also change your whole form depending upon how much energy is sucked up from the feet. Often your hands will seem to have a life of their own, twisting and spiralling, opening and closing as you perform each posture. Other times it will be more subtle with only minute changes in the hands.
However, when you learn tai chi and once you have reached this level of practice, the change will be tremendous in both your health in body and mind and also in your martial ability. Too many instructors keep their students at the same level all of their lives, never telling them about these aspects. So the student thinks that that is all there is to learning tai chi or Baguazhang. They physically stop any new movements from happening because they were not taught that way. So they never really get to see the final stages of training when all of the great benefits manifest.
How To Know
The way to know when you have reached this level, is that when you perform your form, you will simply be contented! That's the only way to describe the feeling after having performed either the Bagua form or the Taiji form. Your whole body will be buzzing and you just want to do things, or just sit and stay calm. If you are an artist, you will wish to begin a new work, or if a musician you will want to write that new song that has been going around in your head for ages.
When you learn tai chi being balanced is a wonderful thing, and being balanced causes one to put his or her life into perspective, not worrying about what so and so is saying about him on the latest 'ego' Taiji forum on the net, or not even thinking about negative things. You want to help people more and more to gain what you have found in your own training.