knight504 said:
How are we defining 'easy to escape'? Because Tayuya's genjutsu seemed especially difficult to break if anything.
I meant 'easy to escape' relative to other genjutsu, not that it's objectively easy to break the genjutsu. Basically, if a genin can even theoretically break the genjutsu by hurting themselves then the genjutsu is "fragile"; it probably wouldn't work on a badass jounin like Kakashi who would likely resist it with Kai or break out by biting his lip like Kurenai did.
So dispelling Tayuya's genjutsu is relatively easy compared to similarly ranked genjutsu - it's only indirectly difficult to escape because the genjutsu typically prevents the victim themselves from actually performing the physical actions required to dispel it. Another unaffected person could probably release the victim pretty easily with a Kai.
In comparison, a jutsu like the Mist Servant Technique is much less debilitating (it only causes visual hallucinations and has no effect on other senses or body control) and therefore presumably far more difficult to dispel than Tayuya's. (Or at least I assume it is, since nobody who was trapped in that genjutsu even attempted to dispel it and I don't think that is because they were too stupid to try.) I think a Kai from a genin would not have had any effect on that genjutsu and Sakura and Sasuke recognized that fact so they didn't waste their chakra trying (while Kabuto was pretending to be weak and Naruto probably didn't even know how to perform a Kai.)
knight504 said:
I'm particularly curious on how some genjutsu knock you unconscious, some genjutsu leave you immobile and others don't interfere you physically at all. What's the difference?
I assume it all depends on which chakra coils in the brain are being manipulated by the genjutsu.
For example, the Temple of Nirvana probably puts people to sleep by messing with the Suprachiasmatic nucleus within the hypothalamus region of the brain, which regulates circadian rhythm, and by causing the brain to release Adenosine which is a hormone that promotes sleep and suppresses arousal (Caffeine works by blocking the cell receptors that bind to this hormone, preventing it from working.)
Genjutsu that leave you immobile are likely suppressing the motor cortex region of the brain, which is involved with the planning, control, and execution of voluntary movements. Or they could be hijacking the brain stem in order to block the signals from the motor cortex from reaching the spinal cord and travelling out to the rest of the body (which would explain why the victim can usually still move their mouths in order to talk.)
Genjutsu that don't interfere with bodily control are just messing with other parts of the brain that aren't responsible for movement. For instance, the Mist Servant Technique which causes visual hallucinations is almost certainly manipulating the occipital lobe, which is the visual processing center of the brain.
Mind control genjutsu probably work by fucking with the limbic system, which is a set of brain structures that support a variety of functions including emotion, behavior, motivation and long-term memory. (Sasori's Memory-Concealing Manipulative Sand Technique likely messes with this same part of the brain, except it uses a surgically implanted needle rather than chakra.)
knight504 said:
Can genjutsu blocks affects more than just truth serum (how does that part work?) and mind reading?
I imagine they could interfere with any kind of foreign chakra invading the brain. So not just mind reading, but also stuff like genjutsu and mind body switch.
I would guess that truth serum is some kind of chakra infused chemical that messes with brain chemistry in a way that suppresses willpower and increases submission. Like a drug version of a genjutsu.
knight504 said:
What would genjutsu traps entail and does it only apply to mind reading which hardly seem to be common overall?
Perhaps genjutsu traps (and genjutsu blocks as well) are fuuinjutsu seals placed directly on the brain, similar to how Madara placed a seal on Obito's heart. Genjutsu blocks probably just interfere with any hostile chakra that enters the brain, while genjutsu traps work like that Amaterasu that Itachi sealed in Sasuke's Sharingan and spring counter genjutsu on anyone trying to send their own chakra into the brain.
knight504 said:
Do you need to specifically affect at least one of a person's five senses to catch them in a genjutsu in the first place?
No, there are plenty of genjutsu that don't affect any of a person's five primary senses. For example, putting someone to sleep or messing with their sense of direction.
knight504 said:
And why do some genjutsu have random visual effects like floating leaves or falling feathers? Why not just jump to the main effect?
For the same reason that body flicker often involves a puff of smoke, a burst of leafs, or a flurry of sand. It's a stylistic choice by the user to personalize the jutsu and/or just to look cool for the people reading the manga.
Also I would like to point out that despite what the databooks say, Izanagi very clearly is not a genjutsu.