Board Thread:Versus Debates/@comment-32104334-20170525071858/@comment-734582-20170525204515

Kakashisologod1 wrote: The thing is tsukuyomi happens in a 1 sec,unlike other genjutsus. But that is also a disadvantage. After all, it speeds up the perception of time for the victim (making a second feel like three days). So in stead of having just one second, the pair would have the equivalent of three days to figure it out.

AsianReaper wrote: They could break them out, but in the second or two that it takes, a whole lot of damage has already been done. Well judging from Edotachi vs Bee or Bee vs Sasuke, there's indeed a one or two second gap. But the caster doesn't know what the victim sees, they can't know if it's broken instantly. E.g. Bee vs Sasuke. So attacking a person freshly under Genjutsu is immensely dangerous for the caster unless they know precisely what they're doing (which is why most genjutsu casters tend to wait and check if it really did catch on).

Sure the Sharingan can catch disturbances in the Chakra, but we don't know how long that takes to assess. Fractions of a second can be a big difference.