While Ichigo underwent training to gain his own Shinigami powers, Kisuke Urahara put Ichigo's soul through a process called Encroachment in which if Ichigo did not gain the power on his own, he would become a Hollow. After three days in the shaft, Ichigo begins to transform into a Hollow. Ichigo exits the shaft in a large explosion resulting from the awakening of his Shinigami and Hollow powers. He succeeded in gaining his power, yet emerged from the Shattered Shaft with Shinigami robes and a Hollow's mask. Thus Hollow Ichigo came about.