The Rasengan is a powerful A-Rank technique invented by the Fourth Hokage, which he created by observing the Tailed Beast Ball. After spending three years developing it, he never saw the Rasengan completed, having never achieved the desired results before he died.
Minato's idea for the Rasengan was to take the Shape Transformation of one's chakra to the "highest possible point" and then combine it with his chakra's nature affinity, creating a jutsu that did not need the aid of time-consuming hand seals to control. He died before he could accomplish this, but on shape transformation alone, the Rasengan is still a very useful, powerful, and difficult jutsu to learn and master.
Users
Minato Namikaze
Jiraiya
Naruto Uzumaki
Kakashi Hatake
Konohamaru Sarutobi
Classification
Ninjutsu
Type
Wind Release
Rank
A-rank
Class
Offensive
Range
Short-range