ok i made an account just so i could share this theory as im always reading these forums, and nobody thought of this but has questioned it
Ok, one of the key characteristics of Tobi is his mask that displays only ONE sharingan, and this sharingan has NEVER been seen deactivated. However we know that Tobi had always had 2 sharingan due to his fight with Konan and the use of Izanagi through the right hidden eye.
my theory is that this hidden eye was permanantly set as EMS, just as the displayed eye was permanantly activated. It was through this that Tobi was able to become intangible and teleport without the use of handsigns or any apparant eye jutsu. Tobi hid this eye as it was NOT the eye of Madara, and so showing it would foil his false identity. i mean think about, if your going to show one eye why not the other?
Now here's the important part, Tobi used this eye during the fight with Konan, so i believe that in order to survive that battle, Tobi sacrificed his time/space jutsu, knowing that he would gain the rinnegan anyway. Have we seen him teleport since his battle with Konan? or has he been jumping through trees with his 6 paths trailing behind him?
One big question now is, if this theory is true, who's EMS is providing the time/space jutsu?
1 small flaw in this is why Tobi used the EMS eye for Izanagi and not the ordinary one. perhaps you cannot control which eye is used but then again i think Danzou intentionally saved Shisui's eye from being used by Izanagi.