Board Thread:Theories and Speculation/@comment-30381420-20170117052222/@comment-27924662-20170122091853

Thekillman wrote: As shown in the Gokage summit, it's fairly easy to detect. Especially in a village with Sharingan and Byakugan, it would be really hard to hide such a jutsu in such an influential person.

But Danzo had the well-being of the village in mind. He wanted to become Hokage when the time needed him, but he was also aware that he was able to do far more from the shadows. So it's unlikely he would just Koto his lifelog friend to get what he wants, especially since he can't use the jutsu very often and is better off using it to defend Konoha. Ao didn't detect kotoamatsukami... He just sensed shisui's chakra. And asked for explanation. Noone can detect Koto unless by hunch he guesses that could he be in genjutsu?(something what Ao did, Even with sharingan too one won't be able to guess it for the very same reason).