what the rasengan
The Rasengan is a technique invented by Minato Namikaze, the Fourth Hokage, after three years of development, it was never completed. The Rasengan was meant to be an example of nature manipulation as Minato meant to combine his chakra element with the Rasengan. However, he died before he could accomplish this. Despite this, the Rasengan is still a very useful, difficult to learn, jutsu.