You begin practice by setting your feet apart, directly under your shoulders, and parallel. You take a deep but gentle breath in, setting your posture as straight as you can from the top of your head to the center of your feet. Then you exhale and settle in, relaxing your arms by your sides. Now the internal work begins.
You start by focusing your attention on your breath – seeing that your inhale and exhale are even and smooth. You let go of any external concerns and allow yourself to be fully present, consuming your awareness in the task of feeling the subtle sensations of your inner body. Then you begin to breathe with your lower torso, relaxing your low abdomen, waist, and lower back, and allow the whole area to gently expand on your inhale and relax on your exhale.
Breath is an aspect of posture. Posture is an aspect of breath. In a single word: relax.
When we breathe, particularly if we breathe properly, our entire structure shifts. Our spine bends, our sacrum tucks, our ribs expand, our belly and waist expand, the muscles in our throat and pelvic floor contract, and even our hips and shoulders may make minor shifts.
On the other side of the coin, misalignments and chronic patterns of tension and weakness in our body structure may inhibit breath participation in certain areas of the body and permit too much expansion in other areas. Therefore, proper postural alignment plays a key role in efficient breathing.
The goal and purpose of tai chi (also taiji) practice is to develop a body and mind that functions by the tai chi principle. That principle is the harmonization of opposites so that perfect balance is maintained. There are three key concepts to understand before you can begin to apply this principle effectively: Wuji, Yin-Yang, and Taiji.