Wind Release: Rasenshuriken

The Wind Release: Rasenshuriken is a shuriken-shaped variant of the Wind Release: Rasengan.

Overview
The Rasenshuriken was invented by Naruto Uzumaki shortly after he figured out the principles of the Wind Release: Rasengan. Like that technique, Naruto typically has the help of two shadow clones in the Rasenshuriken's formation: he provides the chakra, one clone helps keep the chakra contained, and the second clone adds his wind nature. Unlike the Wind Release: Rasengan, additional shape transformation is applied to the Rasenshuriken, creating four large points around the central Rasengan core, giving the appearance of a fūma shuriken. It also gives off a loud screeching noise. By the time of The Last: Naruto the Movie, Naruto is able to create Rasenshuriken without aid.

The Rasenshuriken requires a great deal of chakra to perform. Naruto has been shown creating as many as three Rasenshuriken on his own before tiring out. While in Sage Mode, he can create two Rasenshuriken per transformation. After the second, he must re-enter Sage Mode in order to be able create additional Rasenshuriken. However, after improving his Sage Mode he's able to use three at a single time (five in the anime), and while in his Kurama Mode or Nine-Tails Chakra Mode, he can use the Rasenshuriken an unlimited number of times. Its four points are very sharp, enough to cut through rock and disintegrate most of Pain's Human Path.

After travelling a certain distance or colliding with a target that it can't slice through, the central sphere of the Rasenshuriken detonates, producing a vortex of wind in the immediate area. Within this vortex, countless microscopic wind blades are created, so many that even the Sharingan can't count them all. The wind blades damage anything within the vortex on a cellular level, attacking the chakra circulatory system to such a degree that no amount of medical ninjutsu can heal it. Tsunade likens the damage to poison, and warns that if the damage is great enough, those affected by it won't be able to use jutsu again.

Development
When Naruto first starts using the Rasenshuriken there are two flaws to using it: It was prone to sporadically dissipate after being formed, forcing Naruto to use it as a melee weapon to keep it stable, thrusting the Rasenshuriken into targets in the same way that he does the standard Rasengan. The Rasenshuriken causes cellular damage not only to his targets, but to the arm Naruto holds the Rasenshuriken with, though the damage isn't quite as severe. It, however, poses enough risk for Tsunade to demand it never be used again.

Naruto is able to overcome these flaws by learning senjutsu. By coating the Rasenshuriken in senjutsu chakra, its shape is maintained after formation, meaning that he can use it as a projectile and, as a result, that he no longer needs to worry about damaging himself. When thrown, the Rasenshuriken travels very quickly, enough to cross the crater of Chibaku Tensei in under a second!

Once thrown, Naruto can remotely expand the Rasenshuriken to either compensate for imprecise aim or to catch dodging targets, though its speed is great enough that this is rarely necessary. He enjoys similar benefits while using Nine-Tails Chakra Mode, where he can use his chakra arms to guide the Rasenshuriken to its target while he remains at a safe distance. Moreover, he can use these chakra arms in place of the usual shadow clones.

Naruto eventually starts making the Rasenshuriken a template for other jutsu, just as he does with the regular Rasengan. Like the Rasengan, some of the simpler modifications he makes to the Rasenshuriken are by using multiple simultaneously or making them larger (or even smaller). In place of the Rasengan he uses for the centre of the Rasenshuriken, he can use Tailed Beast Balls or Truth-Seeking Balls that will create significantly larger explosions upon detonation. He can also apply other natures to the Rasenshuriken, as he does with the Super Tailed Beast Rasenshuriken.

Trivia

 * Though the technique debuted in chapter 339, Naruto used it off-panel six chapters earlier.
 * Like the Rasengan, the Rasenshuriken's colour is depicted inconsistently in the series because Masashi Kishimoto has yet to decide upon a colour for the technique. It is most often depicted as being a bluish-white, but different promotional and supplementary material have also shown it as red or orange with no obvious pattern.
 * In Naruto Shippūden the Movie: The Will of Fire, Hiruko tries to absorb this technique, but was unable to combine the peak-levels of shape and nature transformation, like Naruto did at first. The sphere begins forming in his hand, but it becomes unstable and disperses, backfiring on him.
 * In certain games, when the senjutsu version of the Rasenshuriken is thrown, it will hit and carry its target into the air before exploding. This version is referred to as the.