  We study numerically a stochastic differential equation describing an
interface driven along the hard direction of an anisotropic random medium. The
interface is subject to a homogeneous driving force, random pinning forces and
the surface tension. In addition, a nonlinear term due to the anisotropy of the
medium is included. The critical exponents characterizing the depinning
transition are determined numerically for a one-dimensional interface. The
results are the same, within errors, as those of the ``Directed Percolation
Depinning'' (DPD) model. We therefore expect that the critical exponents of the
stochastic differential equation are exactly given by the exponents obtained by
a mapping of the DPD model to directed percolation. We find that a moving
interface near the depinning transition is not self-affine and shows a behavior
similar to the DPD model.
