The Bengali tantric yogi Purnananda Yati composed the Sat-Cakra-Nirupana around 1577 as a section within a much larger work, the Sri-Tattva-Cintamani, giving it a systematic description of six centers, cakras, arranged along the body's central channel from the base of the spine to a point between the eyebrows, with a seventh center at the crown treated somewhat separately as the seat of final union rather than as one of the six in sequence. For each center the text specifies a number of lotus petals, ranging from four at the lowest center to a thousand at the crown, an associated element, earth, water, fire, air and ether from the lowest four centers upward, a presiding deity and goddess, a Sanskrit seed syllable, bija mantra, inscribed on the petals, and a particular quality of consciousness or spiritual attainment associated with awakening that center.
Running through and connecting all of them is Kundalini, a coiled serpent power the text describes as lying dormant at the base of the spine until yogic practice awakens it and draws it upward through each center in turn toward union with consciousness at the crown, the central image that gives the tradition's alternate English name, the serpent power. Purnananda wrote for practitioners already trained in tantric method, and the text assumes considerable prior familiarity with Sanskrit technical vocabulary and ritual visualization rather than explaining its system from first principles for an uninitiated reader.