  We discuss the physical impacts of the ``Cho decomposition'' (or the
``Cho-Faddeev-Niemi-Shabanov decomposition'') of the non-Abelian gauge
potential on QCD. We show how the decomposition makes a subtle but important
modification on the non-Abelian dynamics, and present three physically
equivalent quantization schemes of QCD which are consistent with the
decomposition. In particular, we show that the decomposition enlarges the
dynamical degrees of QCD by making the topological degrees of the non-Abelian
gauge symmetry dynamical. Furthermore with the decomposition we show that the
Skyrme-Faddeev theory of non-linear sigma model and QCD have almost identical
topological structures. In specific we show that an essential ingredient in
both theories is the Wu-Yang type non-Abelian monopole, and that the
Faddeev-Niemi knots of the Skyrme-Faddeev theory can actually be interpreted to
describe the multiple vacua of the SU(2) QCD. Finally we argue that the
Skyrme-Faddeev theory is, just like QCD, a theory of confinement which confines
the magnetic flux of the monopoles.
