Board Thread:Naruto Discussions/@comment-12509038-20140902023453/@comment-4271790-20140902190507

JOA20 wrote: Kishi retconnected the Susanoo=Tsukuyomi+Amaterasu equation. As Sasuke said, it's enough to have awakened the Mangekyo Sharingan in both eyes to use it. Sasuke himself has yet to use Tsukuyomi, which makes me wonder wheter he actually has it. In his left eye, Sasuke has Amaterasu, in his right eye Kagutsuchi which allows him to apply Shape Transformation to Amaterasu, a feat that even Itachi never showed. Madara has never shown any other MS ability besides Susanoo, which actually disappoints me. If Madara really had Tsukuyomi and Amaterasu, I'd wonder why he never used them. The information on access to the Susanoo was probably retconned. The databook said one must awaken the Tsukuyomi and the Amaterasu to awaken Susanoo. The problem with that databook is, one, only Itachi was shown to have Susanoo at the time, and two, that same databook said that Tobi is Madara. Meaning that databook is outdated. Then the manga (through Sasuke) states you need the "Double Mangekyo," meaning to have awakened (or received) two identical Mangekyo Sharingan. More specifically, each Mangekyo Sharingan eye must awaken a Mangekyo technique. For Itachi, those two techniques were Tsukuyomi and Amaterasu. For Sasuke, it was Amaterasu and Kagutsuchi. For Kakashi, whose usage of Susanoo further supported the fact that the double Mangekyo was necessary, it was the usage of Kamui in both eyes in order to have access to the Susanoo. In that context, the techniques Madara and Indra's eyes individually awakened are unknown and probably won't ever be known.

Edit: And by the way, the Susanoo is ridiculously awesome.