Board Thread:Versus Debates/@comment-32466165-20170722022140/@comment-5085906-20170823125956

^Itachi was shown using MS techniques with his regular Sharingan long before the Mangekyo Sharingan was properly revealed. We had no idea what Itachi's different Sharingan pattern was at the time. And Obito was mostly shown using Kamui with his regular Sharingan in anime-only episodes, in Road to Ninja the non-canon movie and the game-only Ninja Escapades which are semi-canon at best. Even then, he was depicted doing so erroneously and it was most likely oversight by the animators. Whatever instance of them using MS techs with regular Sharingan in the manga was probably corrected in the tankobon version.

And Sasuke's Rinnegan is unique in the sense that it can channel the techniques from his right eye, the Sharingan, but if you've noticed in the Gaiden arc he can use Amenotejikara even when his MS is not active, proving that it's a Rinnegan technique.