Board Thread:Theories and Speculation/@comment-31099706-20170327120301/@comment-25122992-20170327192939

Of course, had he used basic Sharingan, Sasuke and Zetsu would've quickly noticed that Itachi was going easy on Sasuke on purpose. Also, Itachi planned to push Sasuke to his ultimate limits in order to cause Oro appearing and then seal him along with Sasuke's CS, without MS techniques it wouldn't even be possible.