Overrating? Dude 1 tail powered Kakashi was gonna kamui away the mothafckn Juubi, this is a joke by comparison
Show me a single manga scan that suggests Itachi knows anything about Kamui or how it works.
I'll wait. Cuz if he did, and he knew Kakashi had the same ability as Tobi, Itachi wouldn't have been duped into thinking Tobi was Madara all along.
First of all I said Itachi must have an idea about Kamui because he said, that Tobi/Obito who he thought as Madara when Tobi met him before Uchiha clan massacre is in short Teacher/accomplice of Itachi..And here is the scan
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Now why Itachi said that??
Because Obito must have met him before Uchiha clan massacre and must have taught him more things about Mangekyo Sharingan, and since Kamui is Obito's technique I think he could have displayed it to Itachi, so I think that Itachi had knowledge about Kamui, and speculated that Tobi isn't Madara uchiha but someone else who is using Madara's name in disguise...
And that's why he planned about Amaterasu which activates while making eye contact with Obito's eyes, as a safety measure so that Sasuke won't fall in wrong hands and that's what happened when Obito met Sasuke for the first time..
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Considering the intelligence that Itachi had, I don't see this as impossible thing...
And sorry for making you wait, it took me a lot of time to search for those scans...