Dōjutsu
Byakugan
The Byakugan (白眼; "Evil Eye" or "All Seeing White Eye"; Literally meaning "White Eye") is a dōjutsu kekkei genkai of the Hyūga clan. Those that inherit the blood of this clan have almost featureless white eyes. When the Byakugan is activated, the user's pupils become more distinct, and the veins near their temples bulge. It is assumed that all members of the Hyūga clan possess the Byakugan. It is one of the three great dōjutsu, along with the Sharingan and the Rinnegan.
Abilities
The first ability of the Byakugan gives the user a near 360º field of vision, except for one blind spot at the back of the neck above the third thoracic vertebra.
The second ability is being able to see through solid objects, and can use a degree of telescopic sight. The distance and the degree of telescopic sight varies from person to person, and can be improved. However, the Byakugan cannot see through certain (very powerful) barriers.
The third and one of the greatest uses of the Byakugan is the ability to see chakra, as well as the chakra circulation system inside another's body. It is from this particular ability that they are able to employ their ultimate attack style: Gentle Fist. Unlike the Strong Fist, which is focused on external injuries, the Gentle Fist style focuses on internal injuries. Each strike, when placed correctly, strikes along the chakra pathway system, which is the network of vessels that carry chakra. This network is closely intertwined with the functioning of the body's organs, and so, when the keirakukei take damage, the organs suffer as well. There is no defense against the Gentle Fist, since one cannot train one's internal organs to become stronger. The only possible defense is to stop the Gentle Fist's hits from connecting.
Particularly skilled users of the Byakugan can take the Gentle Fist style one step further. Along the keirakurei are 361 pinprick-sized nodes called tenketsu, or chakra points. When struck, the Byakugan user can choose to either seal, or forcibly open these tenketsu, thus giving the user complete control over their opponent's chakra system. So, with precision, all those points along the victim's body can be sealed, stopping the chakra flow to those areas. Able to strike without force, and yet do more damage to a ninja than some of the most powerful ninjutsu, the Gentle Fist is the greatest taijutsu style known in all of Konohagakure.
Sharingan
The Sharingan (写輪眼; Literally meaning "Copy Wheel Eye", Meaning "Mirror Wheel Eye") is a Dōjutsu Kekkei Genkai, which appears in the members of the Uchiha clan. It is one of the three great dōjutsu, along with the Byakugan and the Rinnegan.
Stages
The Sharingan is not automatically activated in the user by birth. It is only first unlocked under some stressful or emotional condition after which the Sharingan may be used freely. When the Sharingan is first activated by a user, it has a different number of tomoe (巴) around the central pupil, varying between users. The wielder of the Sharingan, through continued use and training, evolves it further which involves gaining more tomoe, up to a maximum of three per eye. As the Sharingan evolves, the user gains heightened abilities.
Abilities
The first of the Sharingan's powers is being able to see the chakra flow. The Sharingan can tell if a person is under a genjutsu because the person's chakra flow would be irregular.
The Sharingan's second-most prominent ability grants the user an incredible clarity of perception, allowing them to easily recognize genjutsu and different forms of chakra, though not to the same extent as the Byakugan. This also allows the user to pick up on subtle details, enabling them to read lip movements or mimic something like pencil movements. As the Sharingan evolves, gaining more tomoe seals, this ability extends to being able to track fast-moving objects before finally giving some amount of predictive capabilities to the user. However, even though the user may be able to see an attack or know it is coming, their body may not have time to react.
The Sharingan's third and most well-known ability is that it grants the user the ability to memorize any technique that he or she witnesses, apart from other Kekkei Genkai techniques. The user can memorize ninjutsu, genjutsu, and taijutsu with perfect accuracy, allowing the user to use the techniques as his own, or even modify them to create his own new techniques. In order to reproduce a copied jutsu, however, one must have the necessary skill or ability to perform them. A prime example was Rock Lee's brand of taijutsu. While Sasuke was able to copy some of Lee's moves, they put a much more significant strain on him since he hadn't trained nearly as much as Lee has. In addition to physical skill and kekkei genkai techniques, the Sharingan cannot reproduce jutsu dependent on other factors, such as summons that the user has not signed a contract with.
The Sharingan's final commonly-used ability is capable of inducing a unique brand of hypnosis that involves suggesting actions and thoughts to the opponent through simple eye contact. When used against animals, the eyes of the target take on the pattern of the users Sharingan while under its influence. When used in conjunction with the other aspects of the Sharingan, this allows the user to perfectly mimic every move their opponents make even before they do, making it appear as if the user can "see the future". More advanced Sharingan users can take the hypnosis ability even further by tricking or even trapping their opponent within an illusion. It also allows for other forms of hypnotism, such as putting an opponent to sleep, replaying memories to someone else, or creating various illusions to fool an opponent. The potency of the Sharingan's illusion is dependent on the user's knowledge and skill with implementing genjutsu.
In addition to these commonly used techniques, the Sharingan allows the user to perform the genjutsu Izanagi. Using Izanagi, the user can warp reality for a short amount of time, changing reality into illusion and illusion into reality. However, this technique has been dubbed kinjutsu, because use of it causes the user to go blind.
Mangekyo Sharingan
The Mangekyō Sharingan (万華鏡写輪眼, Mangekyō Sharingan; Literally meaning "Kaleidoscope Copy Wheel Eye") is a heightened form of Sharingan. The Mangekyō Sharingan gives the user access to powerful and forbidden techniques. The Mangekyō Sharingan is distinguished from a normal Sharingan through its appearance, which changes the form of the tomoe seal. Unlike in the case of the Sharingan, the appearance of the Mangekyō Sharingan differs from user to user.
To acquire the Mangekyō Sharingan, the person closest to the Sharingan user must die and the emotion of the loss is responsible for unlocking it. To expedite this occurrence, Uchiha throughout history have killed their closest friends or family members in order to meet this criteria. It is interesting to note that in order to obtain the Mangekyō Sharingan, one must feel the emotion of losing a friend, the act of killing them or watching them die alone will not activate it.
Over time, use of the Mangekyō Sharingan's techniques deteriorates the user's eyesight to the point of blindness. Only by taking and transplanting the eyes of another who also wields the Mangekyō Sharingan can the vision be restored, a process that results in the creation of the Eternal Mangekyō Sharingan (永遠の万華鏡写輪眼, Eien no Mangekyō Sharingan). Not only does this process restore one's eyesight, but it also gives the person greater power.
Rinnegan
The Rinnegan (輪廻眼; Literally meaning "Samsara Eye") is said to be the most revered and powerful of all the three great dōjutsu. The Rinnegan's occurrence is so rare that Jiraiya once believed its existence was only a legend, and Kakashi Hatake believed it to be only a mutation. The Rinnegan is characterized by a ripple-like pattern around the pupil, with a grayish-purple iris and sclera.
Abilities
In addition to enabling the user to quickly master various jutsu, the user may also use all six forms of chakra nature transformation which literally allows its user to use any technique they wish. It also allows the user to use all of the six paths techniques, a series of ninjutsu unique to the Rinnegan user. Like the Sharingan and the Byakugan, the Rinnegan also allows the user to see chakra, including otherwise hidden barriers. The possessor of the Rinnegan can also control the seventh path of Pain, who is "beyond life and death", that can use the Outer Path: Samsara of Heavenly Life Technique, which allows the Rinnegan user to revive all people who have recently died.
