From the recent chapter 643 we can see that obito is going to use his black chakra tecnique to protect him from the bijuu damas should they explode. But why won't he just use kamui to avoid the explosion? I believe he is gathering chakra in his sharingan in order to use infinite tsukuyomi. As a result he can't use his sharingan abilities for some time. Despite the juubi being immensely powerful it seems that projecting a genjutsu of that caliber on the moon requires time to gather chakra in his sharingan. This is the only reasonable explanation I can think of beside it being plot no jutsu. Before anyone says kakashi would attack him if he goes intagible. He can use onmyoudo to protect him. Which means raikiri will be useless. Taijutsu won't damage him due to him surviving more brutal attacks like tobirama's infinite exploding tags.. But what are your thoughts?