The most recognized mediums for casting Genjutsu are Vision-Based from Doujutsu and Sound-Based Genjutsu from the Sound Element. In addition to those however, there are more specialized mediums used, such as physical contact used in the recognized fighting style, Lazy Fist. The Three Tails has a special ability to cast Genjutsu from the mist it creates. Other mediums can be through scent, like those from Perfume Release. In rare cases, elements can be used as mediums for Gens, but only a select few are capable of doing so. Jakai said. He then followed up by answering the second part of his sensei's question.
Unlike the traditional method of casting Genjutsu that is done by disrupting the opponent's chakra network directly and affecting their brain, these methods first require a medium to come in contact with the opponent. For Sight-Based Genjutsus, eye contact must be made. For Sound-Based Genjutsus, the opponent must hear something. For Touch-Based Gens, the opponent must have made physical contact with the user in one way or another. The key difference to note is that these types of Genjutsu must pass through the mediums and hit the target before taking effect . Also, these techniques, generally speaking, should be more powerful than standard Genjutsu.
