The word Taiji first appeared in Book of Changes of the Zhou Dynasty. The essay says: “Where there is Taiji, there is peace and harmony between the positive and the negative.” Taiji means supremacy, absoluteness, extremity and uniqueness. Taiji Quan takes its name for the implication of superiority. Taiji Quan got its name when Shanxi secular Wushu master Wang Zongyue used the philosophy of the positive and negative from the Book of Changes to explain the principles of the boxing.
It is more interesting than any kind of boxings you called Shadow Boxing. If you get chance to vist China, I'll show it to you.