±± Genjutsu ±±
Genjutsu, or Illusionary Arts, unlike ninjutsu, don't produce a real, palpable, feasible effect; it produces an illusionary effect. With a specific KG however, the illusions can become so strong that the body will be fooled into mimicking in real life the fake effects its perceiving through the illusion. There exists two types of Genjutsu: the passive, non chakra fueled ones (basically illusions to our senses like visual paradoxes and such which have little use in the RP and can be easily overcome through experience and logic) and the active, chakra fueled ones. Within the active chakra fueled ones two subtypes exist: Dojutsu induced Genjutsu and Normal Genjutsu.
Genjutsu works by using chakra to disturb the chakra flow of the opponent, specially in the brain, altering his senses. By doing this you can make him perceive any thing his senses are capable of: pain, heat, cold, tickles, iching, etc etc. A ninja can make the opponent taste, smell, feel, see or hear anything he wants. However, because this is done by using your chakra to manipulate his chakra flow, the ninja needs to be close or, many times, have direct eye contact or even physical contact. This is the main limitation of Genjutsu: range. The further you are away from your opponent, the harder it is to induce the fluctuation on his chakra flow to produce the genjutsu.
How exactly does it work? Well, every one has a balanced chakra flow. The chakra flows in a balanced combination of both physical and spiritual energies. The ratio between them vary from person to person (that is how each person has a different chakra signature) but its always calm and balanced. To produce a genjutsu, a ninja uses his chakra to disturb that balance in a controlled way. This is done in a similar way to ninjutsu, throught both focusing and molding chakra. A fluctuation is then created in the targets chakra "wave length" and makes it fluctuate in a given way. This produces the illusion by scrambling the users link between his Spirit and his Body which effectively is the link between his mind and his senses. To make your chakra be capable of doing the correct fluctuation, you need to use, most of the times, handseals. These help you mold and shape and focus your chakra to the correct wave length you want to induce, thus enabling you to use it to disturb the targets chakra flow.