Neidan

Neidan, “inner elixir” or “inner alchemy”, is the Daoist practice of refining the energies of the body and mind to attain health, longevity and, ultimately, union with the Dao. It borrows the language of outer alchemy, the making of elixirs from minerals, but places the furnace, the ingredients and the transformation within the practitioner.

Its basic terms are three treasures: essence (jing), energy or breath (qi) and spirit (shen). Through breathing, meditation, visualization and the circulation of energy, essence is refined into energy, energy into spirit, and spirit returns to emptiness, the Dao. The practice is often described as the dual cultivation of one’s nature (xing), the mind, and one’s life (ming), the body’s vitality.

Inner alchemy took shape in the Tang and Song dynasties; Zhang Boduan’s Awakening to Reality (1075) became a classic. The Quanzhen school made it central to its monastic life, interpreting the elixir above all as the clarified mind. Similar practices of breath and subtle energy are found in Indian yoga and Tibetan Buddhism.