Yin–Yang Release (陰陽遁, In'yōton, Onmyōton, English TV: Shadow and Light Style) techniques make simultaneous use of Yin Release and Yang Release. Yin relates to one's spiritual energy and Yang relates to one's physical energy, and it's necessary to utilise both of these in order to mould chakra for ninjutsu. As such, the basis of simply kneading chakra and using techniques is based in Yin-Yang Release. According to Yamato, the manipulation of Yin and Yang is the source of non-elemental techniques such as the Shadow Imitation Technique, Multi-Size Technique, medical ninjutsu, genjutsu, etc.
Hagoromo Ōtsutsuki, also known as the Sage of the Six Paths, had such a mastery over the Yin–Yang Release that he used Yin to create form from nothing, and then used Yang to breath life into what he had created. According to Tobi, the Sage's technique was called Creation of All Things (万物創造, Banbutsu Sōzō), which he employed to create the tailed beasts out of the chakra from the Ten-Tails. The technique Izanagi is based on this technique.
After receiving power from Hagoromo, Naruto Uzumaki developed the ability to use Yin–Yang Release to stabilise life forces and restore missing organs through physical contact. However, there appears to be a limit to the extent to which this power can heal. For example, Naruto was able to resuscitate Obito, but both were aware that his death was unavoidable when the latter was struck with the All-Killing Ash Bones, Naruto's power could do nothing to prevent him from crumbling to dust nor was he able to restore the broken bones in Guy's leg, as a result, Guy spent the remainder of his life wheelchair-bound.
As Tobirama Senju noted, Yin–Yang also has the ability to nullify the effects of all ninjutsu, rendering them useless. Obito and Madara Uchiha demonstrated this from their usage of the Truth-Seeking Balls. According to Sasuke Uchiha, combining his Six Paths Yin Power and Naruto's Six Paths Yang Power, which was acquired via Hagoromo granting them his chakra, was the only possible method to seal a being as powerful as Kaguya Ōtsutsuki.