Board Thread:Naruto Discussions/@comment-37302121-20190324174107

So, I know how the most genjutsu are used, they need a medium to affect one or more senses of their desired target. The only thing I'm confused on is some genjutsu don't seem to need this from how it comes off. When Kurenai first faced off against Itachi, she just vanished into thin air to play a trick on Itachi's sight.

Another example I have that bothers me is when Hiruzen was fighting Hashirama in part one. Hashirama used the bringer of darkness genjutsu to take away Hiruzen's sight, but there was no medium when he used this jutsu. I notice some people describe genjutsu as either something internal and external.  