Board Thread:Boruto Discussions/@comment-43689784-20200520151938/@comment-9782468-20200531060032

It's chapter 321, after Kakashi demonstrated the Rasengan. I believe it's page 13, but that may be off a few pages.

No, it wasn't established by the manga. Unless you can point to me the chapter where it says the Sharingan can't copy it due to its high level of chakra control. I can give you a bit of a spoiler though; that chapter doesn't exist. The only variant of the Rasengan that's been shown to be too difficult to copy is the Rasenshuriken. In a filler. Even so, The Sharingan can only copy if the user has the skill to do the technique in the first place. Since the Rasengan is within Jonin level, high level Sharingan users could most likely copy it.

You say "you don't win debates on subjects based on assumptions" but you literally gave no actual evidence lol