In this study, we apply the densities of geometrically necessary (GN) crystal defects, i.e., GN dislocation and GN incompatibility considering dynamic recovery to the hardening law of a crystal in order to express almost crystal defects as geometrical quantities. Moreover, the quantitative confirmation process of the generations of subdivisions is proposed, and the information of induced grain is introduced into the strain rate sensitivity. A dislocation-crystal plasticity FE simulation is carried out for large deformation of an FCC polycrystal under plane strain condition. Distributions of crystal defects and crystal orientation in a specimen are visualized and the separation of grains is discussed on the basis of the results obtained here.