Board Thread:Versus Debates/@comment-31338621-20190129080042/@comment-32685487-20190209211250

FTG is part of Konoha's history, Tobirama invented and used it, and then Minato used it. It is what earned him the Nickname Yellow Flash. Itachi has studied everything about Konoha, from its techs to its shinobi to its history. He also knew all about Orochimaru's Hydra techniqe and his replacement shedding skin jutsu, and even that the jutsu took a large chunk of chakra from the user. You underestimate Itachi's studious ability on others jutsu, especially someone as famous as the Yellow Flash.