  We propose a novel type of color magnetic condensation originating from
magnetic monopoles so that it provides the mass of off-diagonal gluons in the
Yang-Mills theory.
  This dynamical mass generation enables us to explain the infrared Abelian
dominance and monopole dominance by way of a non-Abelian Stokes theorem, which
supports the dual superconductivity picture of quark confinement. Moreover, we
show that the instability of Savvidy vacuum disappears by sufficiently large
color magnetic condensation.
