Board Thread:Theories and Speculation/@comment-1872728-20160229033316/@comment-734582-20160308221028

MlGshinobi wrote: Konoha easily can solo bijuu though. Easily? no. Yamato only could control Kurama because of the necklace, and even so required considerable effort to do so.

Sharingan requires an expert user, it doesn't seem like any random uchiha can just go about controlling Biju. Else, Kakashi could've seen Kurama inside Naruto's mental space just like Sasuke. And even so, only a handful of people actually controlled Kurama as a free Biju, all people with the Mangekyou.