Abstract
A very general saddle point nuclear shape may be found as a solution of an integro-differential equation without giving a priori any shape parametrization. By introducing phenomenological shell corrections one obtains minima of deformation energy for binary fission of parent nuclei at a finite (nonzero) mass asymmetry. Results are presented for reflection asymmetric saddle point shapes of thorium and uranium even-mass isotopes with A = 226–238 and A = 230–238, respectively.