  Polarized beam gamma p Compton scattering provides a theoretically clean way
to extract the isovector parity violating pion-nucleon coupling constant
$h_{\pi NN}^{(1)}$. This channel is more tractable experimentally than the
recently proposed extraction of $h_{\pi NN}^{(1)}$ from the Bedaque-Savage
process --- polarized target gamma p compton scattering. The leading parity
violating effect is calculated using Heavy Baryon Chiral Perturbation Theory.
The size of the asymmetry is estimated to be ~ 4 10^{-8} for 120 MeV photon
energy.
