Board Thread:Versus Debates/@comment-31338621-20190129080042/@comment-32685487-20190209212708

It is a tech known to 4 of Konoha's kage guards too, who were alive and around during Itachi's time as Anbu etc. Considering how Itachi was and what was stated about him, it would be out of his character to not know of the jutsu and how it works.