Board Thread:Questions and Answers/@comment-9826910-20130618064245/@comment-11477779-20130810045128

If everyone believed Isshin was dead (with the known exceptions) then there'd be no reason why it would occur to anyone. Only a very few really knew the truth anyways. My main question would be why didn't the Soul Society mount some sort of investigation into Isshin's, disappearance? Maybe they did, and guess who headed it up? Aizen! He could've directed it any way he wished and why would any of them question it back then? Personally I think Ichigo being a Shiba dovetails nicely and if Kubo didn't plan it out from the beginning then he got very lucky with how things turned out.