Chidori

The Chidori is a high concentration of lightning chakra around the user's hand.

Overview
The Chidori was created by Kakashi Hatake after he failed to apply his lightning-nature to the Rasengan. He intended for the Chidori to be a weapon used only to protect friends and loved ones. To perform, the user first gathers lightning to their hand; the high concentration of electricity produces a sound reminiscent of many birds chirping, hence the name. The lightning chakra has been shown on occasions to damage the user's hand, peeling the skin and causing it to smoulder slightly, but this does not appear to actually be debilitating. Once the chakra is gathered, users charge at their target and thrust the Chidori into them, piercing them and typically causing fatal damage. Despite the sound it makes, the rapid speed at which it's used makes it useful for assassinations.

The speed at which the Chidori is performed, despite being one of its greatest assets, also represents one of its biggest drawbacks: users move at their target so fast that its causes a tunnel vision-like effect for them. Because they charge in a straight line it is easy for opponents to attack them, and because of the tunnel vision it is difficult for the user to see these attacks, much less react to them. For this reason, most ninja cannot use the Chidori safely. If the user has a Sharingan, however, these drawbacks are overcome: the Sharingan's heightened visual perception prevents the tunnel vision from occurring and its predictive capabilities make it easy for the user to avoid counterattacks. Kakashi's reaction time with the Chidori eventually became so good that he was able to split a bolt of lightning with it, earning his Chidori the name "Lightning Cutter".

The Chidori requires a large amount to chakra to be performed, placing a limit on how many times it can be used per day. In Part I, Kakashi can use it four times per day and Sasuke Uchiha can use it twice per day under his own power. Both increase their limits to an unspecified number in Part II. During Part II, Sasuke demonstrates several variations of the Chidori that have been given shape transformation, such as Chidori Senbon and Chidori Sharp Spear, both of which allow him to attack at a longer range than the Chidori is capable of.

Variants
Sasuke has been shown using the Chidori with different chakra sources to grant his Chidori additional properties:

Trivia

 * can also be translated to "plover".
 * The name Chidori comes from a story about famous samurai Tachibana Dōsetsu: Tachibana was in possession of a famous sword called . One day, while he was still a young man, he was taking shelter under a tree, as it was raining. Suddenly, a bolt of lightning struck him. However, Tachibana used his Chidori to cut the Thunder God inside the lightning bolt, allowing him to survive. After this incident, he renamed his Chidori to.
 * In the original Naruto anime, Chidori looks like a white, sphere-shaped amount of electricity that surrounds the palm. This is corrected in the Naruto: Shippūden anime, where the Chidori is depicted as it is in the manga: a formless coverage of electricity all over the hand.
 * In both Naruto: Ultimate Ninja 2 and 3, players can customise some characters to be able to use Chidori. In the latter case, it is called "Young Lightning" in the English script when used by ANBU Kakashi.
 * Also in some forms of media like the aforementioned games (along with Gekitō Ninja Taisen 4 and Clash of Ninja Revolution 2), Sasuke in his Cursed Seal of Heaven state (both level 1 and 2) often has the ability to perform both the normal version of his Chidori and its Cursed Seal version as separate techniques.
 * In Naruto: Shippūden episode 417, Kakashi is shown shooting lightning bolts from a stationary position.
 * In trailers for Boruto: Naruto the Movie, when Boruto uses Lightning Release via his Kote, it makes the unique sound that Chidori makes, while in the movie, it sounds like a ordinary lightning technique.