The manipulation of Natural Energy itself.
Shizenjutsu (自然術, Natural Techniques) is a unique form of manipulating the flow of Natural Energy around the user to perform techniques similar to that of Ninjutsu. This can range from influencing the surrounding nature, weather and atmosphere, to performing techniques that are difficult to sense or even see. Due to the inherent difficulty of merely absorbing Natural Energy, this set of techniques can only be performed by Sages of the highest caliber.
When collecting Natural Energy to be used, the user under normal circumstances must be still to manipulate the surrounding flow of it around them provided by nature. Though while within Sage Mode, the portion of Natural Energy that makes up their Senjutsu Chakra can also be extracted and used. When the latter is performed, it can cause the remaining amount of time one can be within their Sage Mode to be shortened, or even completely return them back to their normal form. Those who excel in the use of Shizenjutsu are not required to stay still for the aforementioned.