  We discuss the next to the leading order (NLO) electroweak radiative
corrections to the $e^- e^+ \rightarrow f^- f^+ (\gamma)$ cross section
asymmetry, for polarized and unpolarized beam scenario. The left-right and
forward-backward amplitudes, with and without radiative corrections, are
evaluated and compared for various kinematics. The hard bremsstrahlung is
included for arbitrary energy cuts. The radiative corrections are shown to be
significant and having a non-trivial dependency on the kinematic conditions.
The calculations are relevant for the ultra-precise low-energy experiment
Belle~II planned at SuperKEKB.
