Yet even ino's weak mind transfer jutsu took time to escape, So imagine A Kekkei Genkai Genjutsu, especially a Sharingan user, and a Genjutsu expert as ITachi.
And plus you have to know how to disturb your chakra anyway, and disturbing it takes time, and fighting itachi, you could be dead before you even get a chance to begin to disturb it. SO basically once your caught, your a Sitting duck for atleast 30 seconds or More. Breaking a strong Genjutsu is like Naruto's Sage Training. It takes TIME and concetraition, and in a Actual Battle, You Won't Have "TIME,.
And if your not trained in releasing Genjutsu, your gonna keep failing and gonna have to start back over which would get you killed since you'll be dead in a actual battle, cuz no one will give you all that time. (LIke when Jiraiya was trying to teach naruto how to release Genjutsu, Naruto Kept Failing and kept falling in the water cuz he couldnt get it. Then he even tried it when he was fighting the 30% itachi
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