The basis of Tai Chi lies in the transformations of Tai Chi: the duality of movement and stillness, Yin and Yang, opening and closing. Fundamentally, as students of Tai Chi, we seek stillness in movement and movement in stillness. Because movement and stillness tap into the relationship between emptiness and fullness, we see Yin and Yang reflected in them.
From movement comes separation, and from stillness comes convergence. The most motionless moment of stillness always comes before movement, and conversely, the most restless moment of movement always comes before stillness. Thus, Taiji addresses the universal and eternal state of flux that characterizes all in existence.