Rasendama

Being the technique that inspired Urusai to creating the dark matter, the Rasendama is a technique created by Kagemori Seiun who was inspired by the movement that the wind caused in vanes, creating rotating spheres. His plan was to create a ball from the compression of his chakra, creating a kind of circulate small pump of compressed air. So he concentrates a large amount of chakra in the palm of his hand and then compresses it as much as possible, mixing his chakra with air and creating a sort of vacuum inside (because that it appeared the dark staining). By rotating the generated ball to keep the chakra and the air in constant motion, Kagemori can throw it against his target, causing damage.

Trivia

 * Despite having similar names, Rasendama has no relationship whatsoever with 's technique Rasengan.