Board Thread:Questions and Answers/@comment-6207546-20130504124857/@comment-44061-20140704115042

It is not a common thing to know all captains. During the SS arc, Renji didnt know Hitsugaya was captain of the 10th division. This is due to the fact tha most divisions spend alot of time doing their duties spread across the seiretei and rukongai far from one another. Rukia simply may have never known him or about him. What is known is the Isshin went out of his way to not show himself to anyone else in SS even when they were at his house.