Wind Release: Rasenshuriken

The Wind Release: Rasenshuriken was created by Naruto Uzumaki after he mastered the Wind Release: Rasengan.

Overview
By manipulating the wind-natured chakra of the Wind Release: Rasengan, Naruto was able to create four large points, causing the Rasengan to take on the appearance of a giant fūma shuriken, with the Rasengan in the centre remaining a perfect sphere. The technique gives off a loud bell-like screech after being formed. In order to perform it, Naruto requires the aid of two shadow clones; he provides the chakra, one clone is responsible for the shape transformation, and the other provides the nature transformation.

The Rasenshuriken creates countless microscopic wind-blades that damage the body on a cellular level. It produces so many individual strikes that even Kakashi Hatake is unable to count them all with his Sharingan. The wind blades sever nerve channels in the body, leaving the target unable to move after being struck. They also attack the chakra circulatory system, which cannot be repaired by any form of medical ninjutsu. Depending on the severity of the damage, the victim may not be able to perform a technique ever again. Because the Rasenshuriken does cellular damage to Naruto's arm when he first uses the technique without throwing it, Tsunade labelled it a kinjutsu and likens the technique's effects to poison.

When Naruto first uses the Rasenshuriken against Kakuzu, the latter is caught in a vortex of wind blades. Other than the damage done to his cells, Kakuzu's body is left intact after being struck. After Naruto learns to throw the Rasenshuriken, the damage is greatly increased; not only is it capable of cutting through rocky mountains, but when Pain's Human Path is struck by it, most of its body is disintegrated, leaving only the top of its head. Even though it can now be thrown, it can still be thrust into the opponent.

Improvement
Naruto later perfects the Rasenshuriken with Sage Mode. This allows him to throw it at his opponents, and removes the threat of damaging himself with the technique. Another improvement is that the shuriken now expands after it has been thrown, compensating for imprecise aim or fleeing opponents by widening the area of effect. However, he can throw the Rasenshuriken quickly enough that this is rarely necessary. When thrown, the Rasenshuriken becomes Naruto's quickest attack, able to cross an entire Chibaku Tensei crater — which was roughly the size of a small mountain range — in a single second. When it exploded, it took up a large part of that same area.

Naruto can also create and throw this technique in the Nine-Tails Chakra Mode and Tailed Beast Mode respectively. In this form, he can use the extra chakra arms in place of Shadow Clones to create the Rasenshuriken. He can also form a smaller version of it, developed during his training with Killer B. Using his chakra arms, he can guide the Rasenshuriken towards the enemy, allowing him to redirect it back at them, should the initial attack fail.

Drawbacks
In the beginning, the Rasenshuriken required a great deal of chakra to perform, and after creating it three times, using his own chakra, left Naruto extremely fatigued. However, it requires a good deal more chakra to both create and then throw it, which, while in Sage Mode, can be used twice in addition to other Rasengan variants, with a known maximum of three times. This indicates that a thrown Rasenshuriken takes up approximately a third of his sage chakra. He must then re-enter Sage Mode before using the technique again.

In addition to having the Rasenshuriken damage his arm, Naruto had difficulty maintaining the Rasenshuriken's stability when he first used it. It was prone to dissipating before Naruto could reach his target, requiring that he use it as a melee weapon and force it into the opponent, just as he does with the usual Rasengan.

Trivia

 * Though the technique débuted in chapter 339, Naruto used it off-panel six chapters earlier.
 * In episode 168 Naruto forms the technique without the need of his shadow clones.
 * In the second Naruto artbook and in the third databook, when Naruto is in his initial jinchūriki form, the Rasenshuriken is coloured orange. Masashi Kishimoto notes this to be because, like the Rasengan, he had yet to decide upon a colour for the technique. However, as of the colour covers of chapter 453 and 520, it is bluish white.
 * In Naruto Shippūden 3: Inheritors of 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.
 * When thrown in Naruto Shippūden: Ultimate Ninja Storm 2 and Naruto Shippūden: Ultimate Ninja Storm Generations, the Rasenshuriken would trap the target if it hit dead centre where the sphere was, pushing the target into the air and exploding.