Hello, I know that Shotokan and Wado-ryu share a couple of katas. As their moves are a bit different, I like to know if Wado-ryu is preserving the katas as they were in Shotokan when Otsuka left Funakoshi about 1928, or if he developed the katas further, or maybe both, or if he even took older (Shotokan) versions or versions from Mabuni (so maybe they are not Shotokan based katas after all).

Bittmann writes that Otsuka left due to differences, but are there more details about that part of history? From a McCarthy interview I know that he developed the gohon/sanbon/ippon-kumite during the Shotokan times, so he was involved in the creative process. I deduce he wanted something in Karate that the Shotokan people didn't want and I bet he implemented it in Wado-ryu. What is it? Or was it a personal conflict, e.g. with Funakoshi's son? (a trainer of mine hinted this once).

Are there book sources about those backgrounds and ideas going on at that time?