The waist of the spine is the commander in tai chi movement.
All tai chi learners know this principle in tai chi.
Not many know the role of the throat plays in tai chi.
The throat is the second in command according the old tai chi treatises.
As soon as you start to move the waist, you should move the throat* to connect with the waist and place the top part of the spine under the control of the sacrum.
The throat and the sacrum, are the two ends of the spine.
When they are connected, the spine moves as one piece in active motion.
When we keep the throat back and up, it might solve many of our problems
Keeping the head up
It is important to keep the head up throughout the tai chi set.
When the throat moves back and up, it straightens the neck. The jaw should be loose so the chin will drop and the mouth will open slightly. The head will be up as if the spine pushing up the skull.
We all been told by our instructors many many times to smile while doing tai chi. It is hard to smile without tensing up the cheek.
Now we are smiling without trying.
When the throat is back and the mouth opens, the air can be in and out without breathing consciously.
One less thing to worry about. Don't have to ask your instructor when you should breathe in or out.
Keeping the torso relatively upright
It is the best way to keep the head up and let the bottom sink.
The torso will be quite upright and not leaning, especially sitting onto the back leg.
Opening the shoulders
As we move the throat, the shoulders will separate and open wide when they are relaxed with the elbows sinking.
and many more... Give it a try
* if you don't know how to move the throat back and up, try this
Close your mouth and try to swallow, the throat is being sucked up and move back and up.
Now do it with the mouth open and with relaxed jaws.
There is air being drawn in. It is different from the regular sucking the air in to the lung to breathe.