Original

• The original Rasengan was developed by the Fourth Hokage, Naruto's father. This technique is considered the strongest type of form manipulation jutsu. Jiraiya, Naruto's teacher, mentioned that this technique is considered an A-rank level skill and is typically reserved for only high-rank ninjas. Even though this is Naruto's best technique, he hasn't fully mastered its execution as of the April 2011 story arc. He needs to use his clones through the Shadow Clone technique to produce enough chakra output and shape the Rasengan properly at the same time.
  
  

Giant Rasengan

• The Giant Rasengan (Oodama Rasengan) is first used by Naruto in the start of the Naruto Shippuden arc against Itachi, one of the main antagonists of the story. This improved version of the Rasengan is the main result of Naruto's intense training with Jiraiya for three years. The basic characteristics of the jutsu remain largely the same except that Naruto produces this with much more chakra output. While the original Rasengan only focuses on one part of the body on contact, the Giant Rasengan can completely smother the opponent. Jiraiya also uses a slight variation of the Giant Rasengan in his powered-up sage mode against another main antagonist, Pain.
  
  

Rasenshuriken

• Rasenshuriken is Naruto's completely original technique developed through his jutsu training with his first teacher, Kakashi. This technique is made from infusing Naruto's wind element chakra with the form manipulation of the original Rasengan. Akin to its name, the Rasenshuriken appears as a giant shuriken made purely from chakra. This was first used against Kakuzu, a member of the antagonist group, Akatsuki. Upon contact, it destroys the connections between the cells of the body. Although it is shaped like a shuriken, Naruto could not throw this jutsu at the opponent; however, this limitation was surpassed later on in the story as Naruto used his enhanced sage mode abilities to focus his chakra remotely--allowing him to throw it as a shuriken.
  
  

Non-Canon Rasengan Forms

• Naruto used several forms of his Rasengan solely within the anime and the movie spinoffs; as far as the intent of the original author, he never wrote these forms as part of the plot. These Rasengan forms are typically variations of the canon Rasengan types with minor changes in their attack properties; for example, the Crescent Moon Rasengan was solely used in the third Naruto movie, "Guardians of the Crescent Moon Kingdom." The Crescent Moon Rasengan is created through combining the Rasengan with the light of the moon, creating a crescent shape within the sphere of the Rasengan. This increased its piercing power and overall damage.