User blog comment:Godisme/Everything But The Rain Op. 3 Dark of the Moon/@comment-1904799-20130313234809/@comment-5745799-20130322132422

He could've gotten his powers back the way Ichigo did, with Urahara's light-sword-thingy. I actually kinda think this is how Isshin and Urahara know each other. Urahara could've restored Isshin's powers for him.