Genjutsu : are techniques that are employed in the same fashion as ninjutsu, requiring chakra and hand seals. However, the primary difference between the two is that the effects of genjutsu are illusory; instead of attacking the victim's body, like taijutsu or ninjutsu, genjutsu techniques manipulate the flow of chakra in the victim's brain, thus causing a disruption in their senses. Also, every Genjutsu is chakra fueled.
How it works? : Genjutsu works by using your own unique chakra to disturb the chakra flow of your opponent. Specially you use it in the brain of your opponent to alter his senses, by doing so, you can make him perceive any thing his senses are capable of: pain, heat, cold or even itching. You can basically make the opponent see, taste, smell, feel or hear anything you want. However, because this is done by using your chakra to manipulate his chakra flow, you need to be close, have direct eye contact or even physical contact with your opponent. You can say that the main limitation of Genjutsu is the range. The further you are away from your opponent, the harder it will become to induce the fluctuation on his chakra flow to produce the powerful and unique Genjutsu that you want.
How to counter/dispel a Genjutsu?
- The ninja needs to stop the flow of chakra in their body, and then apply an even stronger power to disrupt the flow of the caster's chakra. Likewise by altering your chakra flow through the introduction of foreign chakra you can get out of Genjutsu too. This can also be done by an unaffected ninja by applying a sudden surge of chakra into the affected person or even, for example, entering sage mode.
- Another option is accessible only to Sharingan wielders. Members of the Uchiha clan can break or see through Genjutsu using their Sharingan.
- One more option is through intense pain not caused by the Genjutsu and utilizing the resulting pain to bring their senses back in order.
- I also believe there is a C-rank Ninjutsu called Kai, which can be used to awaken oneself from a genjutsu by pushing the foreign chakra out of your body by using your own chakra ( that's my interpretation, not sure how it works).
Users:
Kurenai, Itachi Uchiha, Obito Uchiha
That's about all I know about it.
Please fill in the gaps if you'd like.