Board Thread:Naruto Discussions/@comment-25442883-20160112162355/@comment-25442883-20160112194954

JouXIII wrote: Simplest explanation:

Sasuke with regular Sharingan and tomoe-less Rinnegan = Not full-powered.

Sasuke with Eternal Mangekyō Sharingan and tomoe Rinnegan = full-powered. I know that, that wasn't question that bothered me, but use of EMS. When he was in 'not full powered state' his rinnegan was active, same way sharingan is. It's like EMS is draining more chakra than Rinnegan.

And it looks like it's not just Rinnegan that allows him to travel between dimensions but EMS and Rinnegan together (aka tomoe Rinnegan)