Senjutsu (仙術, English TV: Sage Jutsu, Literally meaning: Sage Techniques) refers to a specialised field of techniques that allows the user to sense and then gather the natural energy (自然エネルギー, shizen enerugī) around a person.
Main articles: Sage Mode, Sage Transformation and Orochimaru's Juinjutsu Senjutsu practitioners learn to draw the energy of nature inside of them, blending it with their own chakra (created from spiritual and physical energy within the shinobi). This adds a new dimension of power to the practitioner's chakra, resulting in the creation of "senjutsu chakra" (仙術チャクラ, senjutsu chakura). In humans, this new chakra enables the user to enter an empowered state called Sage Mode. Those that can absorb or manipulate senjutsu chakra are known as sages (仙人, sennin). Currently, there are two known ways to learn senjutsu: One being to learn from the toads of Mount Myōboku as Jiraiya and Naruto have done, and the other from the snakes from the Ryūchi Cave where Orochimaru and Kabuto Yakushi learned it.
Generally, senjutsu chakra cannot be used by those untrained in senjutsu, though this is not always the case. Members of Jūgo's clan passively absorb natural energy, mutating their bodies. Because they cannot control the chakra they are creating, they tend to go into berserk rages. Orochimaru would experiment on the enzyme responsible for these rages, and use that as the basis of his cursed seals, which would absorb the wielder's chakra and in return feed them Orochimaru's senjutsu chakra.
- In the anime, the sound of natural energy being gathered to form senjutsu chakra is the same as the one used for the healing green chakra of the Mystical Palm Technique.
- The word senjutsu (仙術) uses the same hiragana: せんじゅつ, as the Japanese art of scrying (占術), possibly an allusion towards the abilities of Sages to sense persons while in Sage Mode.