Is it mandatory for a ninja in Naruto to yell the jutsu they're going to use? If it's not, then doesn't that just give away your attack? And it's not not Naruto. The same goes for One Piece and Bleach (not as much). For example, Luffy always yells Gum Gum Gatling Gun when he uses it. An enemy would kne what coming. So my question is: why do they always yell what they're going to do, in Naruto, One Piece, and somewhat Bleach?