  A bicomplex is a simple mathematical structure, in particular associated with
completely integrable models. The conditions defining a bicomplex are a special
form of a parameter-dependent zero curvature condition. We generalize the
concept of a Darboux matrix to bicomplexes and use it to derive Backlund
transformations for several models. The method also works for Moyal-deformed
equations with a corresponding deformed bicomplex.
