Genjutsu (幻術 lit. Illusion Techniques) is one of the main Jutsu categories, the others being Ninjutsu, Taijutsu, and Senjutsu.
Genjutsu can be broadly classified into two types:
- Ocular Genjutsu
- Sound-based Genjutsu
What it is
While we may be able to identify Genjutsu based on our general knowledge about illusions, it is not always the case. In Naruto, certain techniques that involve reality manipulation are also Genjutsu.
The formal classification is Jutsu that consumes Spiritual Energy only, one of the two components that make up one's Chakra. It is stated many times that Physical Stamina is associated with Yang Release and Vitality, and Spiritual Energy is associated with Yin Release and Imagination. While Taijutsu is the classification that consumes only Physical Stamina, Genjutsu is its Yin counterpart.
Ocular Genjutsu and the Sharingan
Ocular Genjutsu is any Genjutsu that involves eyes, either the user or the victim.
Ephemeral is an Ocular Genjutsu that requires eye contact from the victim, but isn't cast from the user's eye (from Itachi's finger).
Izanagi and Izanami are Ocular Genjutsu cast from the user's eye, but does not require eye contact from the victim.
Ocular Genjutsu is pretty much exclusive to the Sharingan (写輪眼 lit. Copy Wheel Eye), which has two powers, both heavily related to Genjutsu.
- Eye of Hypnotism (催眠眼, Saimingan) allows one to cast Genjutsu through eye contact (but not just for Hypnotism).
- Eye of Insight (洞察眼, Dōsatsugan) allows one to predict or even copy others' movement or use of a technique. With enough mastery, one can even see through the flaws of a Genjutsu and break it.
This is why among the Three Great Dojutsu, the Sharingan is considered as the eye of Genjutsu, the others being Byakugan (Taijutsu) and the Rinnegan (Ninjutsu). There is one more eye which is Tenseigan (Senjutsu) but that is unknown to the Shinobi on Earth until Toneri's attack in the Last.
The Sharingan is only a tool for Genjutsu, and its effectiveness in both offense and defense depends on the mastery of the user.
While one can train to increase their mastery, one who implanted a third-party's Sharingan are not as genetically adapted as one with Uchiha blood. This is seen when Sasuke broke out of Itachi's Tsukuyomi, the Jutsu Kakashi was helpless against even with a Sharingan.
A workaround from not being the Uchiha bloodline is to enhance your physical energy to balance out your Chakra. Danzo implanted Hashirama's Cells to enable himself to implant about 10 Sharingan, as well as to use Izanagi.
Sound-based Genjutsu are produced either from singing e.g. Gama Rinsho, or through certain musical instrument e.g. Demonic Flute.
Sound-based Genjutsu has the advantage of having greater Area of Effect (AoE) than Ocular Genjutsu, hence can affect many people at once. But from what we've seen so far, it is limited in functionality. It has only done basic immobilisation, while the Sharingan was able to do much more.
Uses of Genjutsu
Genjutsu can be further classified into how it is used. In order of difficulty:
- Reality Manipulation
The generic Sharingan was capable of all four uses. However, they are all on the basic levels, and only Mangekyo Sharingan or Rinne Sharingan can achieve them a greater extent in AoE, duration, or applicability.
The most basic use of Genjutsu is immobilisation, where the victim is temporarily paralysed or even loses consciousness. This was proved to be simple and can be casually done even with only the basic Sharingan, especially on fodder Shinobi. Sasuke was able to use this to knock Sakura out with a glance, even with the Bijuu still trapped in his Genjutsu.
Other than with the Sharingan, it was also used by Jiraiya's sound-based Genjutsu, Gama Rinsho, on the Six Paths of Pain. Unlike the Sharingan Genjutsu, this is purely for paralysis with no mental projection involved. The same applies for Tayuya's Phantom Sound Chains.
The most powerful application of this is by Sasuke, which was able to immobilise all nine Tailed Beasts at once, with a single glance. While a basic Sharingan is able to control the Nine-Tails, immobilizing nine targets at the same time apparently can only be done by the likes of Rinne Sharingan, possibly also with the help of Six Paths Chakra, as even Hagoromo himself was mildly surprised by it.
Genjutsu is most commonly used for control, especially for middle-ability Ninjas. The lowest level of application would be considered as Hypnotic Genjutsu, which suggests to the opponent their next move.
Higher levels of application would be for interrogation, like when Itachi was able to force information out of his victims. Such a Jutsu requires greater chakra control. Both Sasuke and Obito was able to use just the basic Sharingan to accomplish this. Unlike hypnotic Genjutsu, the victims have no recollection of the process.
This can be done even when the victim is already unconscious. For example when Kabuto's mind was stuck in the Izanami loop, Itachi was still able to use Sharingan Genjutsu cast from a Mangekyo Sharingan to control his body into releasing the Edo Tensei Jutsu.
Itachi also used his Sharingan to control his crow into flying out of Naruto and even casting Koto Amatsukami onto himself. This means that one can have potentially a long chain of Genjutsu commands from one to another.
The most powerful of this is definitely Shisui Uchiha's Koto Amatsukami, the most powerful Mangekyo Sharingan Genjutsu. Now many people don't know this but like any other Mangekyo Sharingan, Shisui has two different versions Koto Amatsukami in each eye.
The left Koto Amatsukami gives direct instruction to the target, becoming his "ideal" to work towards to. When Itachi used it on himself, it did not seem to have manipulated any memory. On top of that, Edo Tensei can control Itachi regardless of what memory defines him, hence such an action wouldn't have been able to help him overcome the Edo Tensei.
Once the Jutsu is cast, it's effect is permanent on the target, regardless of what happens to the caster. After the Mangekyo Sharingan went back to being a regular Sharingan, and even after the Mangekyo Sharingan was destroyed by Amaterasu, Itachi remains free from Kabuto's control.
There are two types of Genjutsu for projection: subtle and obvious.
The right Koto Amatsukami, the one stolen by Danzo, is an example of Subtle Projection. Whatever it projected was seen by the victim as past experiences, hence acting to the caster's wish completely out of their own free will. (which doesn't classify as "control")
Contrary to popular belief, Koto Amatsukami does not work directly on the brain, and like most other Genjutsu, works on controlling the victim's chakra. However, Koto Amatsukami does not seem to require eye contact as Danzo was able to cast it on Fourth Mizukage without removing the bandages covering his right eye.
Obvious Projection is much easier to perform, albeit still harder than mere immobilization. Madara could cast it on Obito with just the basic Sharingan, but only with the Gedo Mazo was he able to control the dream to any detail. Itachi was able to relay memories to Sasuke, but without the Mazo, he does not have the same control as Madara.
Unlike the subtle projection, the victims know that they are in a Genjutsu.
Itachi's Mangekyo Sharingan ability Tsukuyomi uses this to subject his victims to days' worth of torture in a matter of seconds. According to Kakashi, whether one has the way to escape this Genjutsu doesn't matter. Once being caught in this Genjutsu, Itachi is able to freely manipulate even the passing of time, so that a few seconds can feel like days.
The greatest form of the application comes in the form of Infinite Tsukuyomi, where the Jutsu is reflected off the Moon instead of being cast from the eye. It isn't just a Genjutsu to immobilize them temporarily, it is putting the victims into dreams and forcing them to accept their reality, despite knowing that they are in a Genjutsu.
However, this Jutsu consumes massive amount of chakra. After Madara cast Infinite Tsukuyomi, his 9-Tomoe Rinne Sharingan was reduced to having just 6 Tomoe.
In the 6th Naruto movie, there is also a watered-down version called Limited Tsukuyomi, cast by a Rinne Sharingan with only 7-Tomoe.
While reality manipulation sounds totally out of the world, Izanagi really is just the reverse of a typical Genjutsu. While other Genjutsu turn dream into reality, Izanagi turns reality into a dream. As a result, the Jutsu was able to change destiny.
However, it was only able to ignore certain events, which users usually use to cheat their own deaths.
While it was originally said to only can be used by those with both Sharingan and Hashirama's cells (Danzo and Obito), it was later revealed that one with the Mangekyo Sharingan was able to use it as well (Madara and Itachi).
Unlike Izanagi which is purely reality manipulation, Izanami also involves immobilizing the victims while the events play inside the victim's mind. According to Itachi, Izanami works on the caster and opponents' senses to recreate the same sensation, in order to loop the events in-between.
Despite being classified as Genjutsu, Izanagi and Izanami are very special cases, in which it does not require eye contact, nor do they involves manipulating the chakra flow.
And the most powerful of this application is none other than Creation of All Things Technique used by Hagoromo himself to create the souls Nine Tailed Beasts from his own imagination and bestow them onto the nine parts of the Ten Tails' Chakra. The part where he gave them physical form, however, is not part of Izanagi's power, but the Yang side of it.
This is also heavily implied to be an Ocular Genjutsu as a Rinne Sharingan was seen behind Hagoromo's back when this Jutsu was performed.
How it works
According to Jiraiya, Genjutsu works on opponent's five senses by controlling the chakra flowing through the cranial nerves. This applies to most Genjutsu, such as the generic Sharingan Genjutsu and Tsukuyomi, but not Izanagi.
This does not work on just usable chakra but the life energy in the broader sense, as we've seen animals being trapped in the Infinite Tsukuyomi, or the Nine-Tails being subdued by Madara's generic Sharingan Genjutsu (despite the Nine-Tails having no chakra pathway system).
So all sentient beings with the appropriate perceptive abilities can be subjected to Genjutsu. However, blind people will be immune to Ocular Genjutsu as the user lack the means to administer it.
Izanagi and Izanami are special cases where they do not manipulate the opponents chakra.
Most Ocular Genjutsu are delivered through eye contact. However, Izanagi and Izanami do not require eye contact. Izanagi works on turning reality into a dream, and Izanami works on the opponent's physical senses, whichever they may be. So any living being that has some sort of consciousness or form of perception can be affected by Izanami.
How to counter it
There are some who are naturally immune to Genjutsu. Specifically, those without Chakra, and hence memories, are immune to all Genjutsu that deals with the mind. Izanagi is only an exception because it acts on the user himself, not because it bypasses the chakra rule.
Infinite Tsukuyomi in particular does not affect the undead, like Edo Tensei reanimations and Zetsu-possessed Obito, even though the Sharingan Genjutsu and Koto Amatsukami has worked on Edo Tensei Itachi.
Since most Genjutsu works by manipulating the chakra flowing through the cranal nerves, the most straightforward way to counter the Genjutsu is to disrupt your own chakra flow, also called Genjutsu Kai (幻術解 lit. Illusion Technique Dissipation).
While it is easy for a third party to do it, releasing yourself from a Genjutsu presumably requires great mental strength to create a chakra disruption large enough to offset the original. Great mental strength happens to be an attribute of Indra rather than Asura. Which is why Naruto often rely on others to release himself from Genjutsu.
Having greater chakra control is key to Genjutsu Kai.
While Tailed Beasts themselves are susceptible to Genjutsu, they can easily release their Jinchuriki from a Genjutsu, provided that the two are in good terms. Otherwise, not only can the Sharingan user control the Jinchuriki (Yugara), one can also control the beast itself (Kushina).
One can also break a Genjutsu by being subjected to a more powerful Genjutsu. Through their Mangekyo Sharingan, Sasuke and Itachi used Sharingan Genjutsu and Tsukuyomi respectively to break each other out of Kabuto's Phantom Sound Chains.
However, this method does not work on certain Genjutsu that either
- Does not work on manipulating chakra e.g. Izanagi
- Can manipulate time experienced such that enough damage is done to one's sanity before he was released e.g. Tsukuyomi
Most Ocular Genjutsu work on eye contact, hence the blind or those who lack vision will be immune to such Genjutsu. Kabuto purposely shut off his vision in order to counter Itachi's Tsukuyomi.
Being much more powerful than the regular Tsukuyomi, Infinite Tsukuyomi was able to penetrate and see through even shadows, making it impossible to avoid even when the victim was sleeping.
However, Sasuke's Susanoo was able to block the light thanks to his Rinne Sharingan, which make him later hypothesize that "Rinnegan Genjutsu can probably be dealt with Rinnegan".
Madara himself was unaffected by his own Genjutsu reflected from the Moon due to his both eyes being Rinnegan already.
Genjutsu that does not require eye contact cannot be blocked. Izanagi works on the user himself, therefore it does not require a subject. Izanami works on the subject's physical senses, whichever they may be.
During the Cast
In the anime, Genjutsu Tree Village uses Chilli Pepper Bomb to break out of Genjutsu by triggering the sense of smell from reality.
Triggering pain as the sense of touch also works. Kurenai dispelled Itachi's genjutsu by biting her lip and Shikamaru broke out of Tayuya's illusions by breaking his finger.
One can even use their own vision against an Ocular Genjutsu. For example, Sasuke mastered his Sharingan well enough to see through the flaws of Itachi's Tsukuyomi.
The last is predicting the casting of Genjutsu. By using Sharingan or Sage Mode precognition, one can predict the Ocular Genjutsu by noticing the Chakra gathered in the eyes.
By using a Sharingan, Obito can see Rin's Chakra being disturbed, and deduce that she is under a Genjutsu.
The Byakugan is even better at this as not only it can see that the chakra is disturbed, but how it was distrurbed specifically.
Infinite Tsukuyomi Counters
Now despite the Infinite Tsukuyomi having the greatest scale, it actually has many weaknesses exclusive to itself.
Firstly, it does not work on the undead, namely those in Edo Tensei and Black Zetsu-possessed Obito. The basic Sharingan Genjutsu and Koto Amatsukami have both shown to work on Edo Tensei Itachi, though both are in his favour and are anticipated by him beforehand.
Lastly, it can be dispelled just by having someone who possesses the Rinnegan and all of the Bijuu Chakra to weave the rat sign, which is probably what Hagoromo did when dispelling those in the first Infinite Tsukuyomi. In Naruto and Sasuke's case, they just had to weave the sign simultaneously.