  To realize massive pions, we study variations of the holographic model of
massless QCD using the D4/D8/anti-D8 brane configuration proposed by Sakai and
Sugimoto. We propose deformations which break the chiral symmetry explicitly
and compute the mass of the pions and vector mesons. The observed value of the
pion mass can be obtained. We also argue a chiral perturbation corresponding to
our deformation.
