Board Thread:Theories and Speculation/@comment-31338621-20200901181802/@comment-26636534-20200911183707

@Brain

Well, I guess I see it differently then. I see Itachi forcing Kakashi's brain to experience getting stabbed over and over, for three days, far more complex than what was done to Naruto at the beginning of part 2.

Which is why I'm skeptical of Itachi taking action and sustaining Tsukuyomi simultaneously. If we assume greater complexity, then we also have to assume greater focus required.