Cracks were introduced in a Si bulk single crystal by a Vickers indentation and foil specimens which contain the cracks in the plane of foil were prepared using a focused ion beam technique. The configuration of the cracks and the defect structures near the indentation were observed by transmission electron microscopy at 1000 kV. The cracks were classified into two groups, a halfpenny crack and a lateral crack. The emission of dislocations near the crack tips was observed by both an in-situ heating and a post-mortem heating experiment.