  We discuss the supersymmetric formulation of the nonhermitian $\beta = 2$
random matrix partition function with one bosonic flavor. This partition
function is regularized by adding one conjugate boson and fermion each. A
supersymmetric nonlinear $\sigma$-model for the resulting Goldstone degrees of
freedom is obtained using symmetry arguments only. For a Gaussian probability
distribution the same results are derived using superbosonization and the
complex orthogonal polynomial method. The symmetry arguments apply to any model
with the same symmetries and a mass gap, and demonstrate the universality of
the nonlinear $\sigma$-model.
