While many edge dislocations can be emitted from the tip of a Mode I crack, the distribution of these dislocations turns out to be dependent on the number of available slip systems as well as the order of emission. This study deals with the situation in which the edge dislocations are emitted one at a time and along a slip plane in which the shear stress is the largest. The result shows that most of the dislocations are confined in two or four symmetric planes even though 34 slip planes are available. Dislocations are emitted along two symmetric planes until they are almost saturated and then the emission is switched to another two planes nearby. The switching reduces crack tip shielding so that more dislocations are emitted in four planes than if the emission is limited to two planes. There is a dislocation-free zone near the crack tip whose size increases with the critical stress intensity factor for dislocation emission.