User blog comment:DashingSword/Chapter 397/@comment-1961713-20100329180709

only Urahara and Ryuken (maybe Yoruichi but even any info about Ichigo had been passed up by Urahara to her) knows who is Isshin Kurosaki up until now - not even the Vizards even mentioned a thing about Isshin - Yama-Ji - Kyoraku - Ukitake and Unohana seem unaware of the surename Kurosaki - oh yeah Aizen got some history with Isshin though - he is grinning when Isshin shows up