Board Thread:Versus Debates/@comment-26958911-20151010214426/@comment-25122992-20160104162200

Come on, Itachi must be familiar with every type of genjutsu, sound genjutsu including, so there's no evidence it'd completely catch him off guard, especially when Toad Chaint has no instantaneous effect (preparation time, again), unlike Tauya's genjutsu. And since he has enough intelligence to deduce that the frogs' croaking doesn't suggest something good for him to happen, he'd do everything he can to stop Ma/Pa from completing their chant, regardless if he identifies their effords as sound genjutsu or no. Also, since these preparations immediately reveal users' location, Jiraya and ko have almost no chance to run away and safely hide somewhere. That's why I came to the conclusion that casting the Toad Chant on Itachi would be as easy as to successfully cast Tsukuyomi for the latter.