Board Thread:Naruto Discussions/@comment-26388300-20150723025334/@comment-5273810-20150813030519

Uchiahmasters wrote: Rinnegan as it is IMO the stronger dojutsu and doesn't fade away after awhile (After Toneri's fight with Naruto Toneri's Tenseigan faded away and became a normal Byakugan implying that the Tenseigan is a temporary power up.) For all you know he can turn on and off his Tenseigan. If you are running low on chakra you might need to go to something that consumes less chakra(Byakugan).

You see it makes sense with the Rinnegan not being able to turn off as the Rinnegan that was being used by everyone(Madara's) is linked to Madara. You see with Uchiha the Sharingan is activated by a special chakra in the brain that is the reason you can turn on and off the Sharingan. Without it you can not turn off the Sharingan(example Kakashi with Obito's eye). As Madara was the one who awakened the Rinnegan it operated like his Sharingan and could only turn on and off(or switch to MS and Sharingan) with his Chakra.

Byakugan is different as anyone can turn on and off the eye's power with the only downside presumably being it consumes more from the use if they don't possess the Kekkei Genkai. The simple reason is the lack of the special chakra in the brain. This is also the reason why all Hyuga are born with the Byakugan and why not all Uchiha awaken the Sharingan.

As this difference exists between Sharingan and Byakugan(the "parent" ocular jutsus of the Rinnegan and Tenseigan shown) my theory is since that brain chakra does not exist from Tenseigan's base ocular jutsu that indeed you can turn off Tenseigan just like the Byakugan. I also theorize that the Rinnegan isn't inherently impossible to turn off but is only that way if the Uchiha are the ones who awaken it.

For my theory on the Rinnegan if you meet the requirements and awaken it as a Senju you can turn it on and off at will just like any other Kekkei Genkai. If you need the Sharingan eye then you transplant it like with normal Sharingan and just like with normal Sharingan transplants you can't turn the eye normal. However once the Rinnegan evolves you can turn the Rinnegan aspect on and off just like Madara could except you can't go down further than Sharingan.

So as you can see you assume to much on that account.