Board Thread:Versus Debates/@comment-43403813-20190907005521/@comment-9782468-20191001181255

@BrainBrand he could've noticed Itachi make it before he even joined the fight, watching with his Sharingan. There's no indication that he thought that it was not a clone. There's minor evidence that Kakashi knew it was a clone.

Essentially, my argument wasn't that Kakashi definitely knew that Itachi was a clone. What I'm saying is that saying he for sure did not know that it was a clone is a very big assumption considering there's nothing to back it up.

Regarding your edit, he probably just knew about Clone Explosion technique. He's the Leaf's Number 1 technician, it's not weird for him to know about different techniques.