  We consider a version of QCD dipole cascading corresponding to a finite
number n of discrete steps Delta Y of branching in rapidity. The discretization
scheme preserving the holomorphic factorizability and scale-invariance in
position space of the dipole splitting function, we derive an exact recurrence
formula from step to step which plays the role of a ``discrete-time''
Balitsky-Kovchegov equation. The BK solutions are recovered in the limit
n=infinity and Delta Y=0.
