Board Thread:Versus Debates/@comment-32457608-20170702132834/@comment-25319479-20170705204504

By Itachi's own words, every jutsu has a weakness. In the case of Kotoamatsukami, it can only be cast twice by Shisui before waiting a decade for it to recharge. With Itachi being aware of this weakness combined with his Crow Clone Technique, it's logical to assume that Itachi could fool Shisui into wasting his 2 attempts on his clones. And that ladies and gentle, is how Itachi avoids Kotoamatsukami.