Board Thread:Wiki Discussions and Support/@comment-2140588-20150318152949/@comment-4271790-20150405011602

Because Kishimoto isn't involved in the "other things" such as the anime, novels, movies (with the exception of The Last), video games, etc. The manga is fully canon, because Kishi wrote it. The other things are not fully canon unless Kishi says otherwise. Everything is explained in the link I just gave. Read it, please.