Anyone who has watched, or has seen the Naruto anime, knows that dōjutsu are one of the greatest strengths in anime. Whether the Sharingan, byakugan or rinnegan, both are a kind of power passed from generation to generation through the bloodline. These three main ones are the strongest eye powers in the world of Naruto, and with that I will detail the most famous of him, the Sharingan itself. The eye power that has a tragedy tainted with it, and one of the pillars of the ninja world.
Famous for its black and red coloring, where in its 'maximum' capacity at an earlier level of its evolution, it is formed by three tomoe. The tomoe are the pattern where we can see three 'commas' in the Sharingan itself. Those who have the sharingan worked at maximum capacity, get unique abilities that are able to turn the tables during combat, ensuring the survival of those who have it.
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How to awaken the three tomoe of the Sharingan

For the awakening of the tomoe, both follow a pattern of the Sharingan itself, where the user will awaken 1 to 3 tomoe through a strong emotion. Thus, making it a strongly marked factor in the lineage of the Uchihas, the holders of the eye jutsu. This evolution varies according to the emotion felt by the user, that is, a user can awaken all three tomoe at once if marked by a great negative emotion, such as the loss of someone for example.
When in a matured state (3 tomoe) the user can improve their physical abilities and gain extraordinary reflexes, as well as the ability to copy jutsus more easily. A great example of the gain in skills improvement, it was Sasuke's first confrontation against Naruto in the valley of the end, where the Uchiha was losing, and only managed to keep up with Naruto when his Sharingan matured and started to have the three tomoe.
Unique Abilities Granted to Uchihas

As stated above, Uchihas have a great advantage in combat due to the unique abilities of their eyes. The powers of an Uchiha can vary in two parts, one being called the "Eye of Perception" due to its high ability to adapt and predict enemy movements, as well as the "Eye of Hypnotism" which as its name describes it, the user gains incredible aptitudes for using genjutsu.
With the first ability, the Sharingan user can practically see the color and flow of chakra. Thus, it can differentiate different types of attack or irregularities, facilitating in a combat, where it can form better strategies, besides the gain of physical fitness. But, those who think that the first skill of the dōjutsu is the one that favors him the most are wrong, but the second. The ability and ease in creating genjutsu, where one gains incredible ability to recognize genjutsu, and even achieve different chakra forms to trap the enemy in a jutsu that drives him to despair, as happened to Kakashi in his fight against Itachi.
Now, we also have the clan's most well-known skill, which allows you to copy the enemy's jutsu. Of course, it just doesn't apply to situations where the jutsu is for a kekkei genkai, as well as the sharingan itself, which is the ability inherited from birth and passed down from generations. The user thus gains the ability to memorize ninjutsu, genjutsu, and taijutsu with near-perfect accuracy! Ensuring the user to use the techniques as if they were their own, and even modify them, thus creating their own new technique.
The strongest dōjutsu in Naruto

Although the Sharingan is an incredible eye jutsu, allowing for a vast arsenal of unique abilities granted, as well as the ability to copy enemy jutsu, further strengthening your arsenal. Know that he is not the strongest eye power in the world of Naruto. Despite being the most known and feared, it is not the only one that can strengthen the user, as mentioned above, there are the three great dōjutsu.
The Uchiha clan are users of the famous scarlet eye, and so they are greatly feared, which even led to the extinction of their clan by Itachi in order to avoid an unprecedented internal war. However, know that despite all this, there is a stronger and feared eye power still in Naruto.
The Rinnegan is the pinnacle of all eye jutsu, being carried by a very limited number of people due to its complexity. It can only be extracted by those who have the junction of two types of chakras, the Senju added to the Uchiha. Known as the "supreme eye", the user gains the ability to do everything the Sharingan does, and even more powers. After all, it is an eye of the divine clan, the otsutsuki, those who possess it, can copy jutsu, and use techniques never seen before, including the ability to master the 5 types of elemental jutsus with extreme ease.
Evolution Through Pain – Mangekyou Sharingan!

As if all the power gained by having just one pair of eyes wasn't size and grandiose, there is a level obtained by few Uchihas, but which has tremendous power behind a great sacrifice. Called the Mangekyou Sharingan, it is an evolution above the three tomoe of a matured Sharingan.
But unlike conventional, mangekyou is a more powerful, yet highly destructive form. However, it is not something accessible to all Uchihas, as to awaken such power, it is necessary to go through a much greater trauma than strong emotions to mature the tomoe. The ones we saw with the mangekyou, are characters who have gone through situations where they have led to the death of a very close friend, or brother, or even killing that dearest person for such power.
However, after having such great power, and with unique abilities for each Uchiha, such as Amaterasu and Susanoo. These powers are stronger than the eye of the one who has it can resist. The pressure that is put on the user's eyes becomes so great, that with time and use of this power, it damages the wielder's eyesight, and in time leads to blindness.
Eternal Mangekyou

As time passes, mangekyou users begin to go blind, due to the immense power and price it costs the user. But, it is possible to circumvent this 'necessary evil' to use such powers. It is called the Eternal Mangekyou, and with it the wielder ignores the blinding effect over time. However, know that the fact of drastically reducing the side effects of the eyes, does not prevent the prolonged use of the technique, does not prevent the user from being extremely exhausted by the large consumption of chakra.
To obtain such eyes, it uses a different method, where it is no longer up to the body to evolve naturally, but to take a part of another for itself. Let's use the example of Sasuke and Itachi, where both are brothers. After Sasuke's victory and Itachi's death, Sasuke was able to awaken his mangekyō. However, he was quickly going blind from extreme use, which made him follow a path to nullify these side effects.
And well, and the process was simply transplanting the eyes of Itachi who also possessed the mangekyou, making Sasuke's new eyes along with his chakra awaken a new standard, the eternal mangekyou, with its unique and lethal abilities.
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