Board Thread:Naruto Discussions/@comment-31948035-20170717011649/@comment-25122992-20170717115702

It was rather Kamui than Izanagi. The third databook description implies he used his "mysterious ability" which made him intouchable in combat, and while the databook calls him Madara at that point, this ability still is nothing but Kamui. Also, Itachi knew all about Izanagi, including its history, there's no way he couldn't foresee Obito using it, while Obito himself said he survived only thanks to the "several things kept hidden from Itachi". This hidden info could be only the Kamui mechanics.