In this work the propagation of small surface flaws in polycrystalline ceramics has been computer-simulated in the case of dynamic fatigue. Local effective critical stress intensity factors and subcritical crack growth have been taken into account. It is shown that the rupture stress remains constant with varying initial flaw size in a large size domain. The results are compared and discussed with respect to literature data. Controlled flaws from indentation may be used as mode1 flaws for such investigation in contrast to natural flaws where the adjacent microstructure affects very much the input-parameters for simulation.