Board Thread:Naruto Gaiden/@comment-25380140-20150514070725/@comment-2120712-20150518115711

Even if you are right about 10 years for the crow only, Kishi has not elaborated on how long it took Shisui between uses. Though seeing as his tech was widely known among the affluent(Danzo, Ao, Itachi, Obito, and Kabuto(I doubt Kabuto had any significant political power before his perma leaving of the leaf though) at least) 10 years is a little too long but then again one use of that power would make any shinobi jealous. Too bad shisui didn't get a novel. Could of cleared up a lot. Plus that tech was described as being the strongest of his ms genjutsu so he could of had other but weaker techs ready for use.