Board Thread:Versus Debates/@comment-2245550-20160522071949/@comment-25122992-20160523073616

Techniclly, Sharingan is a copier, but you can't copy something beyond your own abilities. As was already said, Sasuke's physical condition actually allowed him to perform Shadow of the Dancing Leaf, regardless if he copied it or learned by himself. In fact, it's almost the same thing. The Sharingan just allows a better insight in the technique, and if you have the requirements for it, you can easily perform it. What is it if not a fastened learning process?

Now about requirements. What I meant is that Kakashi had to learn a particular nature before being able to copy the techniques of this nature he'd seen with the Sharingan. Have you never asked yourself the question why Kekkei Genkai techniques can't be copied? Yeah, because Sharingan user usually doesn't possess this Kekkei Genkai himself, otherwise he would be able to do so. It's actually the same thing with basic 5 natures - you must already know how to use a particular nature to recreate the natured jutsu you see. So mastering 5 natures wasn't really easier for Kakashi than for Hiruzen, the Sharingan just widened his choice of natured techniques.