Shape Transformation

Shape Transformation is changing the shape and movement of chakra, determining the size, range, and purpose of a jutsu. Rasengan is described as shape manipulation that has been taken "to the highest possible level". The Rasengan relies heavily on chakra control and does not require the use of Hand Seals. By building up on precepts learned during Tree Climbing Practice and Water Surface Walking Practice chakra control exercises, the Rasengan is chakra that has been rotated and then compressed down into the shape of a sphere.

Combining with Nature Transformation
Shape Transformation is one of two necessary techniques for creating a jutsu with its counterpart being Nature Transformation. While Shape Transformation changes the form and movement of chakra, Nature Transformation changes the actual nature of the chakra, altering its properties and characteristics. Because of this, a technique like Rasengan can be turned into Wind Release: Rasengan or Wind Release: Rasenshuriken. The cutting nature of wind-nature can be combined with spiraling movement of chakra, changing the chakra into millions of minuscule blades, in a spiraling formation as seen when used against Kakuzu.